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Ovarian cancer has the highest mortality rate among all gynecological cancers with its pathogenic mechanisms largely unknown. Here, we uncovered that ovarian cancer tissues exhibit higher heterogeneous nuclear ribonucleoprotein A2B1 (hnRNPA2B1) expression than normal ovarian epithelium tissues. Increased hnRNPA2B1 level matches along with poor prognosis of ovarian cancer patients. Importantly, hnRNPA2B1 inhibition hampers growth, reduces mobility of ovarian cancer cells in vitro and hinders xenograft tumor formation in vivo. Transcriptome profiling analysis reveals that hnRNPA2B1 dictates the expression of various important genes involved in tumorigenesis and Lin-28 Homolog B (Lin28B) is down-regulated upon hnRNPA2B1 loss. hnRNPA2B1 regulates expression of Lin28B via binding to Lin28B mRNA and enhancing its stability. Furthermore, knockdown of Lin28B reduces proliferation and mobility of ovarian cancer cells and impairs tumorigenesis in vivo, whereas Lin28B overexpression promotes xenograft tumor formation. Finally, re-expression of Lin28B in hnRNPA2B1 knockdown cells results in rescued phenotypes. Collectively, our results demonstrate that hnRNPA2B1 facilitates the malignant phenotype of ovarian cancer through activating Lin28B expression., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Preeclampsia (PE) is a disease unique to pregnancy and one of the leading causes of maternal and neonatal morbidity and mortality. Our previous study found that Lin28b, an RNA-binding protein stem cell factor, is down-expressed in the placenta of preeclampsia and significantly increases the invasion of HTR-8/SVneo cells in vitro. However, the mechanism of Lin28b's role is unclear. The purpose of this study is to investigate whether Lin28B affects the biological behavior and vascular development of trophoblast cells through miR-92b and downstream signaling pathway DKK1/Wnt/β-catenin. Our study demonstrated that Lin28B promotes trophoblast invasion through miR-92b in HTR-8 cells. Further experiments showed that microRNA-92b could negatively regulate DKK1 expression in placental trophoblasts, thereby inhibiting the activity of Wnt/beta-catenin signaling pathway, thereby inhibiting the migration and invasion of trophoblasts. Furthermore, we explored the expression of DKK1 and β-catenin in the placental tissues of preeclampsia patients and 20 healthy people. This study confirmed that Lin28 acts on DKK1 through miR-92b, which affects the expression of downstream Wnt/β-catenin, inhibits the invasion of trophoblast cells and the development of placental vasculature, and participates in the occurrence of PE.

Various studies demonstrate that long noncoding RNAs (lncRNAs) act as oncogenes or tumor suppressors in cancer. However, the function of lncRNAs in bladder cancer still remains largely unknown. In this study, we identified an lncRNA, gastric cancer-associated lncRNA1 (GClnc1), which was in high abundance in bladder cancer tissues and its expression was related to poor survival rates in patients with bladder cancer. In vitro and in vivo assays showed that GClnc1 significantly promoted cell proliferation, metastasis, and invasiveness in bladder cancer. Mechanistically, we first found that GClnc1 bound to LIN28B and promoted the expression of myelocytomatosis proto-oncogene (MYC) through the LIN28B/let-7a/MYC pathway. In short, GClnc1 is clinically, functionally, and mechanistically oncogenic in bladder cancer. GClnc1 may be a potential target for treating patients with bladder cancer. [ABSTRACT FROM AUTHOR]

Background: Previous investigations have revealed that miR-563 is associated with a number of diseases including the ossification of posterior longitudinal ligament, Parkinson's disease or drug resistance to leukemia. Yet, the role of miR-563 and its molecular mechanism in the initiation and progression of cancers has not been previously explored. In this study, we aimed to provide clues to the function of miR-563 and its direct target in lung cancer., Methods: Online informatics software was applied to predict the target genes of miR-563. MiR-563 targeting LIN28B was evaluated through the luciferase reporter gene analysis. The effect of miR-563 on LIN28B at the level of RNA and protein was detected using RT-PCR and immunoblotting. The ability of proliferation of human lung cancer A549 was examined by MTT assay. RNA interference targeting LIN28B was examined through immunoblotting. The level of miR-563 and LIN28B and their correlation were analyzed in 27 cases of lung tumor tissues by real-time PCR., Results: Oncogenic LIN28B was identified as one of the target genes of miR-563 in lung cancer cells. MiR-563 dose-dependently decreased the LIN28B RNA level and subsequently its protein level in the cells. Cell proliferation was suppressed by ectopic miR-563 expression and was accelerated after endogenous miR-563 was knocked down by its inhibitor. However, silence in LIN28B reversed promotion of cell proliferation by the inhibition of miR-563. In lung cancer tissues, miR-563 was decreased and negative correlation of miR-563 and LIN28B was shown., Conclusion: MiR-563 plays a tumor suppressive role in lung cancer progression via targeting oncogenic LIN28B., (© 2019 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.)

Mesenchymal stem cells (MSCs) transplantation has emerged as a potential therapeutic approach for Alzheimer's disease (AD). However, the poor proliferation capacity and low survival rate of engrafted MSCs in the hostile microenvironment of AD limit their therapeutic efficiency. Lin28B is a conserved RNA-binding protein associated with cell self-renewal and survival. The purpose of the present study was to explore whether lin28B might influence the functions of implanted MSCs and strengthen their neuroprotective potential in AD. A gain-of-function assay was used to upregulate lin28B expression in MSCs by lentiviral transfection. Our in vitro results indicated that lin28B promoted MSCs proliferation and migration, and protected MSCs against Aβ1-42-induced cell death by upregulating insulin-like growth factor-2 (IGF-2). Blockage of IGF-2 partially abrogated the above effects of lin28B. After intracerebroventricular injection into amyloid precursor protein/presenilin 1 mice, implanted MSCs were monitored using bioluminescence imaging. We observed that administration of MSCs transfected with lin28B significantly stimulated their proliferation and prolonged cell retention after delivery. Moreover, administration of the transfected MSCs markedly mitigated cognitive deficits, promoted amyloid plaque clearance, decreased the activation of microglia, and reduced neuronal cell death. The data above confirmed our hypothesis that lin28B is a crucial modulator determining the fate of transplanted MSCs by regulating IGF-2-associated pathways and thereby enhancing their protective effects against AD., (© 2019 Wiley Periodicals, Inc.)

Introduction: There is growing evidence that long non-coding RNAs (lncRNAs) are correlated with malignancy in the modulation of tumor progression. This study aims to investigate the effect of homeobox protein (HOX) transcript antisense RNA (HOTAIR) on the migration and invasion of ESC., Material and Methods: Starbase was used to identify miRNAs with complementary base pairing with HOTAIR. RNA pull-down and qRT-PCR were employed to investigate the effect of HOTAIR on miR-152-3p. In vitro cell migration and invasion assays were performed to assess the effects of HOTAIR and miR-152-3p on ESC. Computational software, TargetScan, was then used to identify the potential target of miR-152-3p, and their relationship was verified by immunoblotting analysis, qRT-PCR and luciferase reporter assay., Results: Starbase predicted a potential miR-152-3p binding site in HOTAIR, which was validated by RNA pull-down assay. HOTAIR was negatively correlated with miR-152-3p in ESC. Moreover, HOTAIR promoted migration and invasion of ESC. The oncogenic activity of HOTAIR was partly through its negative regulation of miR-152-3p. LIN28B was identified to be a direct target of miR-152-3p. A negative correlation between LIN28B and miR-152-3p was observed in ESC. In addition, overexpression of miR-152-3p suppressed the progression of ESC by directly targeting and regulating LIN28B., Conclusions: Our results reveal that HOTAIR may be a driver of ESC through inhibiting miR-152-3p, a tumor suppressor, suggesting that miR-152-3p may be a potential target for advanced ESC therapeutic treatment., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2019 Termedia & Banach.)

Neuroblastoma is a pediatric malignant tumor arising from the sympathetic nervous system. The patients with high-risk neuroblastomas frequently exhibit amplification and high expression of the MYCN gene, resulting in worse clinical outcomes. Vitamin K3 (VK3) is a synthetic VK-like compound that has been known to have antitumor activity against various types of cancers. In the present study, we have asked whether VK3 and its derivative, VK3-OH, could have the antitumor activity against neuroblastoma-derived cells. Based on our results, VK3-OH strongly inhibited cell proliferation and induced apoptotic cell death compared to VK3. Treatment of MYCN-driven neuroblastoma cells with VK3-OH potentiated tumor suppressor p53 accompanied by downregulation of anti-apoptotic Bcl-2 and Mcl-1. Interestingly, VK3-OH also suppressed the MYCN at mRNA and protein levels. Furthermore, we found downregulation of LIN28B following VK3-OH treatment in MYCN -amplified and overexpressed neuroblastoma cells. Collectively, our current findings strongly suggest that VK3-OH provides a potential therapeutic strategy for patients with MYCN-driven neuroblastomas., Competing Interests: There are no conflicts of interest., (© 2019 The Authors.)

Chemoresistance remains a big challenge in hepatocellular carcinoma (HCC) treatment. Several studies indicated that RNA-binding protein Lin28B serves an oncogenic role in HCC, but its activity in HCC chemotherapy has never been assessed. In this study, we found that overexpression of Lin28B significantly increased the paclitaxel chemoresistance in two different HCC cells lines while silencing Lin28B reduced the chemoresistance in paclitaxel-resistance HCC cells. Curcumin, a natural anti-cancer agent, increased the sensitivity of HCC cells to paclitaxel through inhibiting NF-κB stimulated Lin28B expression both in vitro and in vivo . Furthermore, by analyzing TCGA (The Cancer Genome Atlas) LIHC (liver hepatocellular carcinoma) and GSE14520 databases, we found that Lin28B was highly upregulated in HCC tissue compared with that in normal tissue and associated with α‑fetoprotein levels, and that patients with Lin28B higher expression had a significant shorter overall survival time than those with Lin28B lower expression. Our data reveal that Lin28B may serve as a predictive biomarker and a treatment target to reverse HCC chemotherapy resistance in future clinical practice., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Background: Inappropriate activation of the proto-oncogene LIN28B and inactivation of the p53 tumor suppressor, have been shown to have a critical role in tumorigenesis. Previous research has shown therapeutic potential for the use of herbal plants as an alternative strategy for cancer treatment. Achillae wilhelmsii C. Koch is a plant that has been traditionally used for its medicinal properties. The aim of this study was to investigate the cytotoxic and apoptosis-inducing effect of Achillea wilhelmsii C. Koch hydroalcoholic extract ( AWHE ) on HeLa cervical cancer cells and its effect on LIN28B and p53 expression., Methods: The cytotoxic activity of AWHE was evaluated on HeLa cells using a trypan blue exclusion assay. The Annexin V/PI double staining assay was used to evaluate the apoptosis-inducing effect of the extract. The expression of LIN28B and p53 mRNA was measured using the real-time-PCR method., Results: Treatment with AWHE was shown to induce cytotoxicity in both time and concentration-dependent manners (P<0.05). The proposition of HeLa cells undergoing apoptosis increased with increasing concentrations of AWHE (P<0.05). The mRNA levels of p53 increased following 12, 24, and 48 hours of AWHE treatment whereas the mRNA levels of LIN28B were significantly decreased after 4 to 12 hours of AWHE treatment (p<0.05)., Conclusion: Our findings confirmed the pro-apoptotic function of AWHE on the cervical cancer HeLa cell line. This indicates that targeting the LIN28B signaling cascade may be a promising therapeutic strategy for cervical cancer. Further research is required to understand the therapeutic effects of AWHE in primary human cervical cancer cells and a pre-clinical cervical cancer model.

LIN28B is an RNA-binding protein necessary for maintaining pluripotency in stem cells and plays an important role in trophoblast cell differentiation. LIN28B action on target gene function often involves the Let-7 miRNA family. Previous work in cancer cells revealed that LIN28 through Let-7 miRNA regulates expression of androgen receptor (AR). Considering the similarities between cancer and trophoblast cells, we hypothesize that LIN28B also is necessary for the presence of AR in human trophoblast cells. The human first-trimester trophoblast cell line, ACH-3P was used to evaluate the regulation of AR by LIN28B, and a LIN28B knockdown cell line was constructed using lentiviral-based vectors. LIN28B knockdown in ACH-3P cells resulted in significantly decreased levels of AR and increased levels of Let-7 miRNAs. Moreover, treatment of ACH-3P cells with Let-7c mimic, but not Let-7e or Let-7f, resulted in a significant reduction in LIN28B and AR. Finally, forskolin-induced syncytialization and Let-7c treatment both resulted in increased expression of syncytiotrophoblast marker ERVW-1 and a significant decrease in AR in ACH-3P. These data reveal that LIN28B regulates AR levels in trophoblast cells likely through its inhibitory actions on let-7c, which may be necessary for trophoblast cell differentiation into the syncytiotrophoblast., (© 2019 Wiley Periodicals, Inc.)

Background & Aims: Alterations of individual genes variably affect the development of hepatocellular carcinoma (HCC). Thus, we aimed to characterize the function of tumor-promoting genes in the context of gene regulatory networks (GRNs)., Methods: Using data from The Cancer Genome Atlas, from the LIRI-JP (Liver Cancer - RIKEN, JP project), and from our transcriptomic, transfection and mouse transgenic experiments, we identify a GRN which functionally links LIN28B-dependent dedifferentiation with dysfunction of β-catenin (CTNNB1). We further generated and validated a quantitative mathematical model of the GRN using human cell lines and in vivo expression data., Results: We found that LIN28B and CTNNB1 form a GRN with SMARCA4, Let-7b (MIRLET7B), SOX9, TP53 and MYC. GRN functionality is detected in HCC and gastrointestinal cancers, but not in other cancer types. GRN status negatively correlates with HCC prognosis, and positively correlates with hyperproliferation, dedifferentiation and HGF/MET pathway activation, suggesting that it contributes to a transcriptomic profile typical of the proliferative class of HCC. The mathematical model predicts how the expression of GRN components changes when the expression of another GRN member varies or is inhibited by a pharmacological drug. The dynamics of GRN component expression reveal distinct cell states that can switch reversibly in normal conditions, and irreversibly in HCC. The mathematical model is available via a web-based tool which can evaluate the GRN status of HCC samples and predict the impact of therapeutic agents on the GRN., Conclusions: We conclude that identification and modelling of the GRN provide insights into the prognosis of HCC and the mechanisms by which tumor-promoting genes impact on HCC development., Lay Summary: Hepatocellular carcinoma (HCC) is a heterogeneous disease driven by the concomitant deregulation of several genes functionally organized as networks. Here, we identified a gene regulatory network involved in a subset of HCCs. This subset is characterized by increased proliferation and poor prognosis. We developed a mathematical model which uncovers the dynamics of the network and allows us to predict the impact of a therapeutic agent, not only on its specific target but on all the genes belonging to the network., (Copyright © 2019 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Delta-like protein 3 (DLL3) has been reported as a biomarker in various human tumors. However, the biological function and mechanism of it in advanced small cell lung cancer (SCLC) is rarely reported. This study was devised innovatively to explore the role of DLL3 in the progression of SCLC. Immunohistochemistry (IHC) analysis was used to examine DLL3 expression in paraffin-embedded SCLC tumor samples. Upregulation of DLL3 reduced chemotherapy sensitivity. Kaplan-Meier analysis was used to analyze the progression-free survival or overall survival of SCLC patients with high or low level of DLL3. The negative association between DLL3 expression and the PFS or OS rate of SCLC patients was identified. Relative high level of DLL3 was determined in SCLC cell lines by using qRT-PCR analysis. Loss-of function assays were performed to detect the biological functions of the silencing of DLL3 in SCLC. As a result, silencing of DLL3 led to the proliferative and migratory inhibition of SCLC cells and reversed EMT process. Mechanistically, DLL3 mRNA was stabilized by the RNA-binding protein lin-28 homolog B (LIN28B). Further mechanism investigation revealed that LIN28B and DLL3 are two downstream targets of miR-518d-5p. Finally, rescue assays demonstrated that LIN28B and miR-518d-5p could regulate DLL3-mediated cell proliferation and migration. Collectively, our present study revealed a novel molecular pathway in SCLC, which providing a new insight in exploring the therapeutic strategy for SCLC., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Choriocarcinoma is a rare and malignant trophoblastic tumor. However, the molecular mechanisms by which choriocarcinoma is regulated remain unknown. In the present study, we first elucidated that LIN28B was highly expressed in human choriocarcinoma tissues and choriocarcinoma cell lines. Our data further demonstrated that knockdown of LIN28B by small interfering RNA caused an increase in Let-7a expression in JAR cells. In addition, silencing of LIN28B inhibited IGF2BP1 expression and suppressed cell proliferation capacity, both of which can be markedly restored by Let-7a inhibitor. In contrast, LIN28B over-expression-improved cell proliferation was inhibited by Let-7a mimic. Knockdown of β-catenin resulted in reduced expression of LIN28B and increased expression of Let-7a. Knockdown of β-catenin also caused a decrease in cell proliferation, which can be recovered by re-expression of LIN28B or by Let-7a inhibitor. Collectively, our data indicate that β-catenin/LIN28B/Let-7a pathway may be crucial for the regulation of cell proliferation in human choriocarcinoma cells., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The Lin28b + Let7 - axis in fetal/neonatal development plays a role in promoting CD5 + B1a cell generation as a B-1 B cell developmental outcome. Here we identify the Let7 target, Arid3a, as a crucial molecular effector of the B-1 cell developmental program. Arid3a expression is increased at pro-B cell stage and markedly increased at pre-B and immature B cell stages in the fetal/neonatal liver B-1 development relative to that in the Lin28b - Let7 + adult bone marrow (BM) B-2 cell development. Analysis of B-lineage restricted Lin28b transgenic (Tg) mice, Arid3a knockout and Arid3a Tg mice, confirmed that increased Arid3a allows B cell generation without requiring surrogate light chain (SLC) associated pre-BCR stage, and prevents MHC class II cell expression at the pre-B and newly generated immature B cell stages, distinct from pre-BCR dependent B development with MHC class II in adult BM. Moreover, Arid3a plays a crucial role in supporting B1a cell generation. The increased Arid3a leads higher Myc and Bhlhe41, and lower Siglec-G and CD72 at the pre-B and immature B cell stages than normal adult BM, to allow BCR signaling induced B1a cell generation. Arid3a-deficiency selectively blocks the development of B1a cells, while having no detectable effect on CD5 - B1b, MZ B, and FO B cell generation resembling B-2 development outcome. Conversely, enforced expression of Arid3a by transgene is sufficient to promote the development of B1a cells from adult BM. Under the environment change between birth to adult, altered BCR repertoire in increased B1a cells occurred generated from adult BM. However, crossed with B1a-restricted V H /D/J IgH knock-in mice allowed to confirm that SLC-unassociated B1a cell increase and CLL/lymphoma generation can occur in aged from Arid3a increased adult BM. These results confirmed that in fetal/neonatal normal mice, increased Arid3a at the pre-B cell and immature B cell stages is crucial for generating B1a cells together with the environment for self-ligand reactive BCR selection, B1a cell maintenance, and potential for development of CLL/Lymphoma in aged mice.

Background: Long non-coding RNAs (lncRNAs) have emerged as important regulators of human cancers. However, the functional roles of lncRNAs and the mechanisms responsible for their aberrant expression in gastric cancer (GC) have not been well characterized. Methods: In this study, we examined the expression of lncRNA UFC1 in GC by qRT-PCR and explored its correlation with clinicopathological parameters. In vitro cell functional assays and in vivo animal studies were performed to determine the roles of UFC1 in GC progression. Results: UFC1 was elevated and predicted poorer prognosis in GC. UFC1 knockdown inhibited while UFC1 overexpression promoted GC cell proliferation, migration, and invasion. UFC1 bound to miR-498 to antagonize its tumor suppressive effect on Lin28b. Suppression of Lin28b by miR-498 could be rescued by UFC1 overexpression, whereas Lin28b overexpression partially rescued UFC1 knockdown-mediated inhibition of GC cell function. Lin28b expression was increased in GC and suggested a co-expression pattern with UFC1. Conclusions: UFC1 has a promoting role in GC progression, at least in part, by acting as a miR-498 sponge and derepressing Lin28b expression, which would provide a novel biomarker for GC diagnosis and prognosis and offer a potential target for GC therapy. [ABSTRACT FROM AUTHOR]

RNA-binding proteins (RBPs) are expressed broadly during both development and malignant transformation, yet their mechanistic roles in epithelial homeostasis or as drivers of tumor initiation and progression are incompletely understood. Here we describe a novel interplay between RBPs LIN28B and IMP1 in intestinal epithelial cells. Ribosome profiling and RNA sequencing identified IMP1 as a principle node for gene expression regulation downstream from LIN28B In vitro and in vivo data demonstrate that epithelial IMP1 loss increases expression of WNT target genes and enhances LIN28B-mediated intestinal tumorigenesis, which was reversed when we overexpressed IMP1 independently in vivo. Furthermore, IMP1 loss in wild-type or LIN28B-overexpressing mice enhances the regenerative response to irradiation. Together, our data provide new evidence for the opposing effects of the LIN28B-IMP1 axis on post-transcriptional regulation of canonical WNT signaling, with implications in intestinal homeostasis, regeneration and tumorigenesis., (© 2018 Chatterji et al.; Published by Cold Spring Harbor Laboratory Press.)

The diversity and complexity of the cancer transcriptome may contain transcripts unique to the tumor environment. Here, we report a LIN28B variant, LIN28B-TST, which is specifically expressed in hepatocellular carcinoma (HCC) and many other cancer types. Expression of LIN28B-TST is associated with significantly poor prognosis in HCC patients. LIN28B-TST initiates from a de novo alternative transcription initiation site that harbors a strong promoter regulated by NFYA but not c-Myc. Demethylation of the LIN28B-TST promoter might be a prerequisite for its transcription and transcriptional regulation. LIN28B-TST encodes a protein isoform with additional N-terminal amino acids and is critical for cancer cell proliferation and tumorigenesis. Our findings reveal a mechanism of LIN28B activation in cancer and the potential utility of LIN28B-TST for clinical purposes., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: The let-7 microRNAs (miRNAs) are frequently dysregulated in carcinogenic processes, including cervical cancer. LIN28 proteins regulate let-7 biogenesis by binding to conserved sequences within the pre-miRNA structure. Nevertheless, recent research has shown that some let-7 miRNAs may escape LIN28 regulation., Objective: Correlate pre-let-7 miRNAs and LIN28B levels in cervical cell lines with different malignancy and HPV content., Methods: Pre-let-7 levels were determined by RTqPCR. LIN28B and other let-7 targets were analyzed by immunoblot. In silico tools were used to correlate let-7 and LIN28B expression and to analyze prelet- 7 sequences and structures., Results: Lin28B protein was detected in all tested cell lines although it was more expressed in tumor cell lines. High levels of pre-let-7c/f-1 and pre-miR-98 were present in almost all cell lines regardless malignancy and LIN28B expression. Pre-let-7g/i were mainly expressed in tumor cell lines, pre-let-7e and pre-let-7-a3 were absent in all cell lines and pre-let-7a-2 showed indistinct expression. LIN28B showed positive correlation with pre-let-7i/g/f-1 and pre-miR-98 in tumor cell lines, suggesting escape from regulation. Sequence alignment and analysis of pre-let-7 miRNAs showed distinctive structural features within the preE region that may influence the ideal pre-let-7 structuring for LIN28B interaction. Short preE-stems were present in pre-let-7 that may escape LIN28B regulation, but long preEstems were mostly associated with high-level pre-let-7 miRNAs., Conclusion: The observed differences of pre-let-7 levels in cervical cell lines may be the result of alternative preE structuring affecting interaction with LIN28B thus resulting in differential let-7 regulation., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Background: Wilms tumor (WT) is the most common urologic cancer in children. However, genetic bases underlying WT remain largely unknown. Previous studies indicated that Lin28 homolog B (LIN28B) level is significantly elevated in some WTs. Enforced expression of Lin28b during kidney development could induce WT. Genetic variations in the LIN28B gene may be related to WT susceptibility., Method: In this study, we aimed to assess the association between LIN28B gene polymorphisms and WT susceptibility in Chinese children. Four potentially functional polymorphisms in the LIN28B gene (rs314276 C>A, rs221634 A>T, rs221635 T>C and rs9404590 T>G) were genotyped in 145 cases and 531 cancer-free controls, using Taqman method. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the associations., Results: Our results showed that the rs314276 CA genotype was associated with a decreased WT risk (CA vs CC: adjusted OR=0.65, 95% CI=0.43-0.98, P=.042). Moreover, we found that carriers of the 1-3 risk genotypes had a significantly increased WT risk when compared to the non-carriers (adjusted OR=1.51, 95% CI=1.03-2.20, P=.035). The association with risk genotypes was more predominant in children 18 month old or younger and in females., Conclusion: In summary, these results indicated that the LIN28B gene rs314276 C>A polymorphism alone and three combined polymorphisms may be able to modify WT susceptibility in Southern Chinese children. Our findings call for further validation in large studies with different ethnicities involved., (© 2017 Wiley Periodicals, Inc.)

MicroRNAs (miRNAs) are able to modulate hepatitis B virus (HBV) replication and play an important role in the pathogenesis of HBV infection. Recently, we have identified that serum miR-125b-5p levels correlated with HBV DNA levels and liver necroinflammation. In the present study, we addressed how miR-125b-5p regulated HBV replication at the different steps, inclduing viral transcription, assembly, and virion production and investigated the underlying mechanisms. We found that miR-125b-5p overexpression increased HBV replication without altering HBV transcription. This is the first demonstration of post-transcriptional miRNA regulation of HBV replication. In contrast, transfection of miR-125b-5p inhibitor resulted in downregulation of HBV replication in hepatoma cells. Further, miR-125b-5p inhibited the phosphorylation of retinoblastoma protein and blocked cell cycle progression at the G1/S phase in hepatoma cell lines. Our results indicate that certain miRNAs are able to arrest the cell cycle at G1 phase and may increase HBV replication. RNA sequencing revealed several liver-specific metabolic pathways regulated by miR-125b-5p, which was also found to suppress LIN28B and induce let-7 family members. Additional data demonstrated that miR-125b-5p targeted the LIN28B/let-7 axis to stimulate HBV replication at a post-transcriptional step.

Lin28B, a Lin28 homologue, represses the biogenesis of let-7 microRNAs (miRNAs), has a role in tumorigenesis, and is considered a potential therapeutic target for various human malignancies. However, the associations between Lin28B and the clinical features and outcomes of patients with pancreatic ductal adenocarcinoma (PDAC) remain unclear. In this study, we explored the clinical significance of Lin28B in PDAC and its association with metastasis by examining tissues from patients with PDAC and elucidated the molecular mechanisms using PDAC cell lines. In patients, high Lin28B expression was significantly correlated with high levels of lymphatic metastasis, distant metastasis and a poor prognosis. Furthermore, the multivariate analysis identified Lin28B expression as an independent prognostic factor in patients. In cell lines, stable silencing of Lin28B inhibited cell proliferation, cell cycle transition, migration and the epithelial-mesenchymal transition (EMT). It also increased the expression of the c-MYC, HMGA2 and KRAS genes, which are targeted by the cancer-suppressor miRNA let-7. Lin28B overexpression in the PDAC cell lines had the opposite effect. In human PDAC samples, high Lin28B expression was associated with decreased let-7 expression and increased c-MYC, HMGA2 and KRAS expression. Thus, Lin28B is a novel marker for predicting the prognosis of patients with PDAC and might be a potential therapeutic target for PDAC., Competing Interests: CONFLICTS OF INTEREST The authors declare no competing financial interests.

Background: Current conventional chemotherapy for acute myeloid leukemia (AML) can achieve remission in over 70% of patients, but a majority of them will relapse within 5 years despite continued treatment. The relapse is postulated to be due to leukemia stem cells (LSCs), which are different from normal hematopoietic stem cells (HSCs). LIN28B is microRNA regulator and stem cell reprogramming factor. Overexpression of LIN28B has been associated with advance human malignancies and cancer stem cells (CSCs), including AML. However, the molecular mechanism by which LIN28B contributes to the development of AML remains largely elusive., Methods: We modulated LIN28B expression in AML and non-leukemic cells and investigated functional consequences in cell proliferation, cell cycle, and colony-forming assays. We performed a microarray-based analysis for LIN28B-silencing cells and interrogated gene expression data with different bioinformatic tools. AML mouse xenograft model was used to examine the in vivo function of LIN28B., Results: We demonstrated that targeting LIN28B in AML cells resulted in cell cycle arrest, inhibition of cell proliferation and colony formation, which was induced by de-repression of let-7a miRNA. On the other hand, overexpression of LIN28B promoted cell proliferation. Data point to a mechanism where that inhibition of LIN28B induces metabolic changes in AML cells. IGF2BP1 was confirmed to be a novel downstream target of LIN28B via let-7 miRNA in AML. Notably, ectopic expression of LIN28B increased tumorigenicity, while silencing LIN28B led to slow tumor growth in vivo., Conclusions: In sum, these results uncover a novel mechanism of an important regulatory signaling, LIN28B/let-7/IGF2BP1, in leukemogenesis and provide a rationale to target this pathway as effective therapeutic strategy.

Lin28A and Lin28B are highly conserved RNA binding proteins with similar structure and functions. Recent studies demonstrated that both of them act as oncogenes and promote cancer progression. However, few researches compared the expression and functions of both oncogenes in human malignant tumors at same time. Additionally, although the expression and role of Lin28B in colon cancer is frequently reported, the expression and functions of Lin28A in colon cancer are largely unknown. In this study, we have systematically evaluated the expressional pattern, mutation status and correlation of both Lin28A and Lin28B in colon cancer tissues for the first time, and compared the roles of Lin28A and Lin28B in the proliferation, migration, invasion and apoptosis of colon cancer cells in vitro. We have showed that they are co-expressed and have functional similarities, however, the molecular mechanisms underlying their similar functions may not be identical. This study contributes to clarify the similarities and differences of Lin28A and Lin28B in colon cancer progression.

Retinal regeneration and repair are severely impeded in higher mammalian animals. Although Müller cells can be activated and show some characteristics of progenitor cells when injured or under pathological conditions, they quickly form gliosis scars. Unfortunately, the basic mechanisms that impede retinal regeneration remain unknown. We studied retinas from Royal College of Surgeon (RCS) rats and found that let-7 family molecules, let-7e and let-7i, were significantly overexpressed in Müller cells of degenerative retinas. It demonstrated that down-regulation of the RNA binding protein Lin28B was one of the key factors leading to the overexpression of let-7e and let-7i. Lin28B ectopic expression in the Müller cells suppressed overexpression of let-7e and let-7i, stimulated and mobilized Müller glia de-differentiation, proliferation, promoted neuronal commitment, and inhibited glial fate acquisition of de-differentiated Müller cells. ERG recordings revealed that the amplitudes of a-wave and b-wave were improved significantly after Lin28B was delivered into the subretinal space of RCS rats. In summary, down-regulation of Lin28B as well as up-regulation of let-7e and let-7i may be the main factors that impede Müller cell de-differentiation and proliferation in the retina of RCS rats., Competing Interests: The authors have no competing financial interests.

The RNA-binding proteins LIN28A and LIN28B have diverse functions in embryonic stem cells, cellular reprogramming, growth, and oncogenesis. Many of these effects occur via direct inhibition of Let-7 microRNAs (miRNAs), although Let-7-independent effects have been surmised. We report that intestine targeted expression of LIN28B causes intestinal hypertrophy, crypt expansion, and Paneth cell loss. Furthermore, LIN28B fosters intestinal polyp and adenocarcinoma formation. T o examine potential Let-7-independent functions of LIN28B, we pursued ribonucleoprotein cross-linking, immunoprecipitation, and high-throughput sequencing (CLIP-seq) to identify direct RNA targets. This revealed that LIN28B bound a substantial number of mRNAs and modestly augmented protein levels of these target mRNAs in vivo. Conversely, Let-7 had a profound effect; modulation of Let-7 levels via deletion of the mirLet7c2/mirLet7b genes recapitulated effects of Lin28b overexpression. Furthermore, intestine-specific Let-7 expression could reverse hypertrophy and Paneth cell depletion caused by Lin28b. This was independent of effects on insulin-PI3K-mTOR signaling. Our study reveals that Let-7 miRNAs are critical for repressing intestinal tissue growth and promoting Paneth cell differentiation. Let-7-dependent effects of LIN28B may supersede Let-7-independent effects on intestinal tissue growth. In summary, LIN28B can definitively act as an oncogene in the absence of canonical genetic alterations. [ABSTRACT FROM AUTHOR]

The Let-7 microRNA (miRNA) family is frequently downregulated in multiple human tumors, including hepatocellular carcinoma (HCC). Our previous report demonstrated that hepatitis B virus X protein (HBx) suppressed the expression of let-7 in HepG2 hepatoma cells. However, the underlying mechanisms were not elucidated. Lin28B is known to negatively regulate the maturation of let-7, and this prompted us to determine whether HBx acts through Lin28B to suppress let-7. Real-time reverse-transcription polymerase chain reaction (qRT-PCR) was performed to examine let-7 expression before and after treatment with c-Myc-and Lin28B-specific siRNAs in HepG2 cells stably/transiently transfected with HBx. mRNA and protein analyses were employed to determine the correlation of HBx, c-Myc and Lin28B in HCC tissues and cells. Cell cycle and proliferation assays were performed to delineate the consequences of Lin28B repression in HepG2 cells expressing HBx. Lin28B was overexpressed in HBx-transfected cells and HBV-infected liver tissues. HBx-c-Myc-Lin28B axis mediated the repression of let-7 in HepG2 cells. Reduced expression of Lin28B inhibited the growth and cell cycle progression of HepG2 cells by derepressing let-7 and repressing c-Myc. There was not only a preliminary HBx-c-Myc-Lin28B-let-7 pathway but also another possible double-negative feedback loop between c-Myc/Lin28B and let-7 in HepG2 cells transfected with HBx, which together induced the deregulation of let-7. Lin28B has the potential to be a novel molecular target in the treatment of HBV(+) HCC.

Although the highly proliferative, migratory, and multi-drug resistant phenotype of human pancreatic cancer stem cells (PCSCs) is well characterized, knowledge of their biological mechanisms is limited. We used CD44 and LIN28B as markers to screen, isolate, and enrich CSCs from human primary pancreatic cancer. Using flow cytometry, we identified a human primary pancreatic cancer cell (PCC) subpopulation expressing high levels of both CD44 and LIN28B. CD44+/LIN28B+ PCSCs expressed high levels of stemness marker genes and possessed higher migratory and invasive ability than CD44-/LIN28B- PCCs. CD44+/LIN28B+ PCSCs were more resistant to growth inhibition induced by the chemotherapeutic drugs cisplatin and gemcitabine hydrochloride, and readily established tumors in vivo in a relatively short time. Moreover, microarray analysis revealed significant differences between the cDNA expression patterns of CD44+/LIN28B+ PCSCs and CD44-/LIN28B- PCCs. Following siRNA interference of endogenous LIN28B gene expression in CD44+/LIN28B+ PCSCs, not only was their proliferation decreased, there was also cell cycle arrest due to suppression of cyclin D1 expression following the stimulation of miRNA let-7b expression. In conclusion, CD44+/LIN28B+ cells, which possess CSC characteristics, can be reliably sorted from human primary PCCs and represent a valuable model for studying cancer cell physiology and multi-drug resistance.

LIN28 is an RNA-binding protein that is expressed in many developing tissues. It can block let-7 (Mirlet7) microRNA processing and help promote pluripotency. We have observed LIN28 expression in the developing mouse neural tube, colocalizing with SOX2, suggesting a role in neural development. To better understand its normal developmental function, we investigated LIN28 activity during neurogliogenesis in vitro, where the succession of neuronal to glial cell fates occurs as it does in vivo. LIN28 expression was high in undifferentiated cells, and was downregulated rapidly upon differentiation. Constitutive LIN28 expression caused a complete block of gliogenesis and an increase in neurogenesis. LIN28 expression was compatible with neuronal differentiation and did not increase proliferation. LIN28 caused significant changes in gene expression prior to any effect on let-7, notably on Igf2. Furthermore, a mutant LIN28 that permitted let-7 accumulation was still able to completely block gliogenesis. Thus, at least two biological activities of LIN28 are genetically separable and might involve distinct mechanisms. LIN28 can differentially promote and inhibit specific fates and does not function exclusively by blocking let-7 family microRNAs. Importantly, the role of LIN28 in cell fate succession in vertebrate cells is analogous to its activity as a developmental timing regulator in C. elegans. [ABSTRACT FROM AUTHOR]

Accumulation of mesangial extracellular matrix (ECM) proteins such as collagen type 1-α2 (Col1a2) and collagen type 4-α1 (Col4a1) is a key feature of diabetic nephropathy (DN). Transforming growth factor (TGF)-β1 plays important roles in ECM accumulation in DN, and evidence shows a mediatory role for microRNAs. In the present study, we found that microRNA let-7 family members (let-7b/c/d/g/i) were downregulated in TGF-β-treated mouse mesangial cells (MMCs) along with upregulation of Col1a2 and Col4a1. Ectopic expression of let-7b in TGF-β-treated MMCs attenuated Col1a2 and Col4a1 upregulation. Conversely, let-7b inhibitors increased Col1a2 and Col4a1 levels. Cotransfection of MMCs with mouse Col1a2 or Col4a1 3'-untranslated region luciferase constructs and let-7b inhibitors increased luciferase activity. However, constructs with let-7 target site mutations were unresponsive to TGF-β. TGF-β-induced 3'-untranslated region activity was attenuated by let-7b mimics, suggesting that Col1a2 and Col4a1 are direct targets of let-7b. In addition, Lin28b, a negative regulator of let-7 biogenesis, was upregulated in TGF-β-treated MMCs. Luciferase assays showed that the Lin28b promoter containing the Smad-binding element (SBE) responded to TGF-β, which was abolished in constructs without SBE. Chromatin immunoprecipitation assays showed TGF-β-induced enrichment of Smad2/3 at the Lin28b promoter, together suggesting that Lin28b is transcriptionally induced by TGF-β through SBE. Furthermore, let-7b levels were decreased, whereas Lin28b, Col1a2, and Col4a1 levels were increased, in glomeruli of diabetic mice compared with nondiabetic control mice, demonstrating the in vivo relevance of this Lin28/let-7/collagen axis. These results identify Lin28 as a new TGF-β target gene and suggest a novel role for the Lin28/let-7 pathway in controlling TGF-β-induced collagen accumulation in DN., (Copyright © 2014 the American Physiological Society.)

let-7 microRNA (miRNA) is implicated in various biological processes, and its downregulation essentially linked to human malignancy. Regulation of gene expression of the let-7 family is critically linked to RNA-binding proteins. For instance, Lin28B and its paralog, Lin28A, inhibit the pre-let-7 precursor from being processed to mature miRNA by recruiting terminal uridyltransferase, TUT4, which adds oligomeric U at the 3' end, suggesting that deregulation of Lin28B, together with Lin28A, may alter various biological processes through modulation of let-7 expression. Here, we showed that the Lin28B protein level is regulated via ubiquitin-mediated proteasomal degradation, and identified the ubiquitin ligase as human TRIM-NHL domain-containing TRIM71. In cells, TRIM71 negatively regulates Lin28B protein stability by catalyzing polyubiquitination. Compared with its paralog, Lin28A, a C-terminal unique ~50 amino acid stretch of Lin28B is essential for TRIM71 interactions and subsequent polyubiquitination. Moreover, the N-terminal RING finger motif of TRIM71 is critical for protein-protein interactions and polyubiquitination of Lin28B, and consequent let-7 expression. Consistent with the let-7 stimulatory role of TRIM71 via Lin28B polyubiquitination, specific knockdown of TRIM71 led to downregulation of let-7 expression. Expression of one of the known let-7 targets, HMGA2, was derepressed after knockdown of TRIM71. We additionally showed that enhanced expression of let-7 is part of a feedback loop that targets TRIM71 3'UTR, which contains two conserved let-7 target sites. Our findings collectively reveal critical aspects of regulatory complexity of let-7 biogenesis at the posttranscriptional level., (Copyright © 2014 Elsevier B.V. All rights reserved.)