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Chemoresistance is a main cause of chemotherapy failure and tumor recurrence. The effects of global protein SUMOylation on chemoresistance in colorectal cancer (CRC) remains to be investigated. Herein, we have proposed that the elevated SUMO2/3-modified proteins confer 5-fluorouracil (5-FU) chemoresistance acquisition in CRC. The SUMOylation levels of global proteins in CRC cell lines were elevated compared with normal colon cell line NCM460. 5-FU treatment obviously reduced SUMOylation of global proteins in 5-FU-sensitive CRC cells including HT29, HCT116 and HCT-8. However, in 5-FUresistant HCT-8/5-FU cells, the expression level of SUMO2/3-modified proteins was increased under 5-FU exposure in a concentration-dependent manner. 5-FU treatment combined with SUMOylation inhibitor ML-792 significantly increased the sensitivity of 5-FU-resistant cells to 5-FU and reduced colony formation numbers in HCT-8/5-FU cells. And UBC9-mediated SUMOylation elevation contributes to 5-FU resistance in HCT116 cells. Moreover, we also identified RREB1 as a regulator of SUMOylation profiling of global cellular proteins via directly binding to the promoter of UBC9. Overexpression of RREB1 promoted 5-FU resistance in CRC, which was partially abolished by treatment of inhibitor ML-792. In conclusion, RREB1-enhanced protein SUMOylation contributes to 5-FU resistance acquisition in CRC. [ABSTRACT FROM AUTHOR]

Cutaneous melanoma is the most dangerous and deadly form of human skin malignancy. Despite its rarity, it accounts for a staggering 80% of deaths attributed to cutaneous cancers overall. Moreover, its final stages often exhibit resistance to drug treatments, resulting in unfavorable outcomes. Hence, ensuring access to novel and improved chemotherapeutic agents is imperative for patients grappling with this severe ailment. Pyrazole and its fused systems derived thereof are heteroaromatic moieties widely employed in medicinal chemistry to develop effective drugs for various therapeutic areas, including inflammation, pain, oxidation, pathogens, depression, and fever. In a previous study, we described the biochemical properties of a newly synthesized group of imidazo–pyrazole compounds. In this paper, to improve our knowledge of the pharmacological properties of these molecules, we conduct a differential proteomic analysis on a human melanoma cell line treated with one of these imidazo–pyrazole derivatives. Our results detail the changes to the SKMEL-28 cell line proteome induced by 24, 48, and 72 h of 3e imidazo–pyrazole treatment. Notably, we highlight the down-regulation of the Ras-responsive element binding protein 1 (RREB1), a member of the zinc finger transcription factors family involved in the tumorigenesis of melanoma. RREB1 is a downstream element of the MAPK pathway, and its activation is mediated by ERK1/2 through phosphorylation. [ABSTRACT FROM AUTHOR]

Summary: Spermatogenesis is a developmental process driven by interactions between germ cells and Sertoli cells. This process depends on appropriate gene expression, which might be regulated by transcription factors. This study focused on Rreb1 , a zinc finger transcription factor, and explored its function and molecular mechanisms in spermatogenesis in a mouse model. Our results showed that RREB1 was predominantly expressed in the Sertoli cells of the testis. The decreased expression of RREB1 following injection of siRNA caused impaired Sertoli cell development, which was characterized using a defective blood–testis barrier structure and decreased expression of Sertoli cell functional maturity markers; its essential trigger might be SMAD3 destabilization. The decreased expression of RREB1 in mature Sertoli cells influenced the cell structure and function, which resulted in abnormal spermatogenesis, manifested as oligoasthenoteratozoospermia, and we believe RREB1 plays this role by regulating the transcription of Fshr and Wt1. RREB1 has been reported to activate Fshr transcription, and we demonstrated that the knockdown of Rreb1 caused a reduction in follicle-stimulating hormone receptor (FSHR) in the testis, which could be the cause of the increased sperm malformation. Furthermore, we confirmed that RREB1 directly activates Wt1 promoter activity, and RREB1 downregulation induced the decreased expression of Wt1 and its downstream polarity-associated genes Par6b and E-cadherin , which caused increased germ-cell death and reduced sperm number and motility. In conclusion, RREB1 is a key transcription factor essential for Sertoli cell development and function and is required for normal spermatogenesis. [ABSTRACT FROM AUTHOR]

Cutaneous melanoma is the most dangerous and deadly form of human skin malignancy. Despite its rarity, it accounts for a staggering 80% of deaths attributed to cutaneous cancers overall. Moreover, its final stages often exhibit resistance to drug treatments, resulting in unfavorable outcomes. Hence, ensuring access to novel and improved chemotherapeutic agents is imperative for patients grappling with this severe ailment. Pyrazole and its fused systems derived thereof are heteroaromatic moieties widely employed in medicinal chemistry to develop effective drugs for various therapeutic areas, including inflammation, pain, oxidation, pathogens, depression, and fever. In a previous study, we described the biochemical properties of a newly synthesized group of imidazo–pyrazole compounds. In this paper, to improve our knowledge of the pharmacological properties of these molecules, we conduct a differential proteomic analysis on a human melanoma cell line treated with one of these imidazo–pyrazole derivatives. Our results detail the changes to the SKMEL-28 cell line proteome induced by 24, 48, and 72 h of 3e imidazo–pyrazole treatment. Notably, we highlight the down-regulation of the Ras-responsive element binding protein 1 (RREB1), a member of the zinc finger transcription factors family involved in the tumorigenesis of melanoma. RREB1 is a downstream element of the MAPK pathway, and its activation is mediated by ERK1/2 through phosphorylation.

Aims/hypothesis: Genome-wide studies have uncovered multiple independent signals at the RREB1 locus associated with altered type 2 diabetes risk and related glycaemic traits. However, little is known about the function of the zinc finger transcription factor Ras-responsive element binding protein 1 (RREB1) in glucose homeostasis or how changes in its expression and/or function influence diabetes risk. Methods: A zebrafish model lacking rreb1a and rreb1b was used to study the effect of RREB1 loss in vivo. Using transcriptomic and cellular phenotyping of a human beta cell model (EndoC-βH1) and human induced pluripotent stem cell (hiPSC)-derived beta-like cells, we investigated how loss of RREB1 expression and activity affects pancreatic endocrine cell development and function. Ex vivo measurements of human islet function were performed in donor islets from carriers of RREB1 type 2 diabetes risk alleles. Results: CRISPR/Cas9-mediated loss of rreb1a and rreb1b function in zebrafish supports an in vivo role for the transcription factor in beta cell mass, beta cell insulin expression and glucose levels. Loss of RREB1 also reduced insulin gene expression and cellular insulin content in EndoC-βH1 cells and impaired insulin secretion under prolonged stimulation. Transcriptomic analysis of RREB1 knockdown and knockout EndoC-βH1 cells supports RREB1 as a novel regulator of genes involved in insulin secretion. In vitro differentiation of RREB1KO/KO hiPSCs revealed dysregulation of pro-endocrine cell genes, including RFX family members, suggesting that RREB1 also regulates genes involved in endocrine cell development. Human donor islets from carriers of type 2 diabetes risk alleles in RREB1 have altered glucose-stimulated insulin secretion ex vivo, consistent with a role for RREB1 in regulating islet cell function. Conclusions/interpretation: Together, our results indicate that RREB1 regulates beta cell function by transcriptionally regulating the expression of genes involved in beta cell development and function. [ABSTRACT FROM AUTHOR]

Ewing sarcoma (EwS) is a rare bone and soft tissue malignancy driven by chromosomal translocations encoding chimeric transcription factors, such as EWSR1-FLI1, that bind GGAA motifs forming novel enhancers that alter nearby expression. We propose that germline microsatellite variation at the 6p25.1 EwS susceptibility locus could impact downstream gene expression and EwS biology. We performed targeted long-read sequencing of EwS blood DNA to characterize variation and genomic features important for EWSR1-FLI1 binding. We identified 50 microsatellite alleles at 6p25.1 and observed that EwS-affected individuals had longer alleles (>135 bp) with more GGAA repeats. The 6p25.1 GGAA microsatellite showed chromatin features of an EWSR1-FLI1 enhancer and regulated expression of RREB1 , a transcription factor associated with RAS/MAPK signaling. RREB1 knockdown reduced proliferation and clonogenic potential and reduced expression of cell cycle and DNA replication genes. Our integrative analysis at 6p25.1 details increased binding of longer GGAA microsatellite alleles with acquired EWSR-FLI1 to promote Ewing sarcomagenesis by RREB1-mediated proliferation. Lee et al. characterized germline variation in the 6p25.1 EwS susceptibility region. Longer GGAA microsatellite alleles at 6p25.1 were associated with EwS risk and the microsatellite showed chromatin features of an EWSR1 - FLI1 enhancer. EWSR1 - FLI1 binding altered expression of RREB1 , promoting proliferation. [ABSTRACT FROM AUTHOR]

Background: Melanocytic neoplasms can be challenging to diagnose. One well‐established diagnostic aid is the detection of copy number variation (CNV) in a few key genetic loci using conventional methods such as fluorescence in situ hybridization (FISH) and chromosomal microarray (CMA). Droplet digital polymerase chain reaction (ddPCR) is a novel, cost‐effective, rapid, and automated method to detect CNV. Methods: We perform the first investigation of ddPCR to assay Ras‐responsive element‐binding protein‐1 (RREB1), the most common CNV in melanoma using formalin‐fixed, paraffin‐embedded (FFPE) melanocytic lesion samples; CMA data are used as the gold standard. Archival samples from 2013 to 2021 were analyzed, including 153 data points from 39 FFPE samples representing 34 patients. Benign, borderline, malignant, and metastatic melanocytic neoplasms were examined. Results: ddPCR showed a sensitivity and specificity of 93.8% and 95.7% using one reference gene, and 87.5% and 100% using a different reference gene for RREB1 gain detection. Conclusions: Here we show that ddPCR can provide inexpensive, rapid, and robust data on the commonest copy number alteration in melanoma. Future development and validation could provide a useful ancillary tool in the diagnosis of challenging melanocytic lesions. [ABSTRACT FROM AUTHOR]

Ectomesenchymal chondromyxoid tumor is a rare and benign neoplasm with a predilection for the anterior dorsal tongue. Despite morphologic heterogeneity, most cases are characterized by a proliferation of bland spindle cells with a distinctive reticular growth pattern and myxoid stroma. The immunophenotype of these neoplasms is likewise variable; most cases express glial fibrillary acid protein and S100 protein, with inconsistent reports of keratin and myoid marker expression. The molecular pathogenesis is poorly understood; however, a subset of cases has been reported to harbor EWSR1 gene rearrangement. Following identification of an RREB1-MKL2 fusion gene by RNA Sequencing in an index patient, a retrospective review of additional cases of ectomesenchymal chondromyxoid tumors was performed to better characterize the clinical, immunohistochemical, and molecular attributes of this neoplasm. A total of 21 cases were included in this series. A marked predisposition for the dorsal tongue was confirmed. Most cases conformed to prior morphologic descriptions; however, hypercellularity, hyalinized stroma, and necrosis were rare attributes not previously emphasized. The neoplastic cells frequently coexpressed glial fibrillary acid protein, S100 protein, keratin, smooth muscle actin, and/or desmin; a single case was found to contain significant myogenin expression. An RREB1-MKL2 fusion product was identified in 19 tumors (90%), a single tumor (5%) had an EWSR1-CREM fusion product, and the remaining case lacked any known fusion gene by RNA Sequencing. The latter 2 cases subtly differed morphologically from many in the cohort. This series illustrates that recurrent RREB1-MKL2 fusions occur in most, perhaps all, cases of ectomesenchymal chondromyxoid tumor.

Mitochondrial adaptations dynamically reprogram cellular bioenergetics and metabolism and confer key properties for human cancers. However, the selective regulation of these mitochondrial responses remains largely elusive. Here, inspired by a genetic screening in acute myeloid leukemia (AML), we identify RAS effector RREB1 as a translational regulator and uncover a unique translation control system for nuclear-encoded mitochondrial proteins in human cancers. RREB1 deletion reduces mitochondrial activities and succinate metabolism, thereby damaging leukemia stem cell (LSC) function and AML development. Replenishing complex II subunit SDHD rectifies these deficiencies. Notably, inhibition of complex II re-sensitizes AML cells to venetoclax treatment. Mechanistically, a short RREB1 variant binds to a conserved motif in the 3' UTRs and cooperates with elongation factor eEF1A1 to enhance protein translation of nuclear-encoded mitochondrial mRNAs. Overall, our findings reveal a unique translation control mechanism for mitochondrial adaptations in AML pathogenesis and provide a potential strategy for targeting this vulnerability of LSCs., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

• High RREB1 expression is linked to poor prognosis in some tumors and affects immunotherapy sensitivity. • RREB1 expression was associated with chemotherapy sensitivity. • RREB1 knockdown inhibits osteosarcoma cell proliferation and wound healing. The Ras-responsive element binding protein 1 (RREB1) is a transcription factor involved in various biological processes. Notably, RREB1 plays a role in tumor immunity by regulating tumor-related gene expression, shaping the tumor microenvironment, and modulating immune checkpoints. Given these functions, RREB1 has emerged as a potential regulatory target in tumor immunotherapy. However, a comprehensive pan-cancer analysis evaluating RREB1's prognostic value and its role in modulating the immune microenvironment remains unexplored, warranting further investigation to better understand its mechanisms across different cancer types and its implications for personalized immunotherapy. We analyzed RREB1 expression across 33 cancer types using RNA sequencing data from the TCGA database. RREB1 alterations were further characterized using the cBioPortal database. Clinical and pathological features, along with prognostic significance, were assessed using TCGA clinical data. The involvement of RREB1 in the tumor microenvironment was evaluated using the CIBERSORT and ESTIMATE algorithms. Relationships between RREB1 expression and tumor mutation burden (TMB), as well as microsatellite instability (MSI), were investigated using Spearman's rank correlation coefficient. GSEA was applied to explore the biological functions of RREB1. Additionally, we assessed the link between RREB1 expression and the efficacy of PD-1/PD-L1 inhibitors. Finally, a series of in vitro experiments were performed to evaluate the impact of RREB1 expression on the malignant behavior of osteosarcoma (OS) and lung cancer cell lines. RREB1 was overexpressed in several cancer types and correlated with patient prognosis. RREB1 expression was strongly associated with TMB, MSI, and immune cell infiltration, including regulatory T cells, CD8+ T cells, and macrophages. Furthermore, RREB1 expression was linked to immune responses and the efficacy of immunotherapy. In vitro experiments demonstrated that knockdown of RREB1 significantly inhibited the proliferation and migration of OS cells. RREB1 shows potential as a prognostic marker for certain cancers and may predict the efficacy of immunotherapy. Additionally, RREB1 expression is related to immune-related markers, suggesting its role in prognosis and predicting responses to immune microenvironment therapies in specific tumors. [ABSTRACT FROM AUTHOR]

Cleft palate is one of the major congenital craniofacial birth defects. The etiology underlying the pathogenesis of cleft palate has yet to be fully elucidated. Dissociation of the medial edge epithelium (MEE) at the contacting region of palatal shelves and subsequent migration or apoptosis of MEE cells is required for proper MEE removal. Ras-responsive element-binding protein 1 (RREB1), a RAS transcriptional effector, has recently been shown to play a crucial role in developmental epithelial–mesenchymal transition (EMT), in which loss of epithelial characteristics is an initial step, during mid-gastrulation of embryonic development. Interestingly, the involvement of RREB1 in cleft palate has been indicated in humans. Here, we demonstrated that pan-Ras inhibitor prevents the dissociation of MEE during murine palatal fusion. Rreb1 is expressed in the palatal epithelium during palatal fusion, and knockdown of Rreb1 in palatal organ culture resulted in palatal fusion defects by inhibiting the dissociation of MEE cells. Our present findings provide evidence that RREB1-mediated Ras signaling is required during palatal fusion. Aberrant RREB1-mediated Ras signaling might be involved in the pathogenesis of cleft palate.

There are multiple independent genetic signals at the Ras-responsive element binding protein 1 ( RREB1 ) locus associated with type 2 diabetes risk, fasting glucose, ectopic fat, height, and bone mineral density. We have previously shown that loss of RREB1 in pancreatic beta cells reduces insulin content and impairs islet cell development and function. However, RREB1 is a widely expressed transcription factor and the metabolic impact of RREB1 loss in vivo remains unknown. Here, we show that male and female global heterozygous knockout ( Rreb1 +/- mice have sex- and diet-specific decreases in adipose tissue and adipocyte size; male mice on high-fat diet had larger gonadal adipocytes, while males on standard chow and females on high-fat diet had smaller, more insulin sensitive subcutaneous adipocytes. Mouse and human precursor cells lacking RREB1 have decreased adipogenic gene expression and activated transcription of genes associated with osteoblast differentiation, which was associated with Rreb1 +/- mice have sex- and diet-specific decreases in adipose tissue and adipocyte size; male mice on high-fat diet had larger gonadal adipocytes, while males on standard chow and females on high-fat diet had smaller, more insulin sensitive subcutaneous adipocytes. Mouse and human precursor cells lacking RREB1 have decreased adipogenic gene expression and activated transcription of genes associated with osteoblast differentiation, which was associated with Rreb1 +/- T2D protective alleles have smaller adipocytes, consistent with RREB1 loss-of-function reducing diabetes risk.in vivo . Finally, human carriers of RREB1 T2D protective alleles have smaller adipocytes, consistent with RREB1 loss-of-function reducing diabetes risk., Competing Interests: Competing interests ALG discloses that her spouse is an employee of Genentech and hold stock options in Roche. All other authors declare no interests that could be considered conflicting.

Chemoresistance is a main cause of chemotherapy failure and tumor recurrence. The effects of global protein SUMOylation on chemoresistance in colorectal cancer (CRC) remains to be investigated. Herein, we have proposed that the elevated SUMO2/3-modified proteins confer 5-fluorouracil (5-FU) chemoresistance acquisition in CRC. The SUMOylation levels of global proteins in CRC cell lines were elevated compared with normal colon cell line NCM460. 5-FU treatment obviously reduced SUMOylation of global proteins in 5-FU-sensitive CRC cells including HT29, HCT116 and HCT-8. However, in 5-FU-resistant HCT-8/5-FU cells, the expression level of SUMO2/3-modified proteins was increased under 5-FU exposure in a concentration-dependent manner. 5-FU treatment combined with SUMOylation inhibitor ML-792 significantly increased the sensitivity of 5-FU-resistant cells to 5-FU and reduced colony formation numbers in HCT-8/5-FU cells. And UBC9-mediated SUMOylation elevation contributes to 5-FU resistance in HCT116 cells. Moreover, we also identified RREB1 as a regulator of SUMOylation profiling of global cellular proteins via directly binding to the promoter of UBC9 . Overexpression of RREB1 promoted 5-FU resistance in CRC, which was partially abolished by treatment of inhibitor ML-792. In conclusion, RREB1-enhanced protein SUMOylation contributes to 5-FU resistance acquisition in CRC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Deng, Chen, Gao, Zhang, Luo, Luo, Li, Fu and Liang.)

Postmenopausal osteoporosis (PMO) is the most common bone disorder in elderly Chinese women. Although genetic factors have been shown to have a pivotal role in PMO, studies on genetic loci associated with PMO in Chinese individuals are still lacking. We aimed to identify SNPs that contribute to PMO in Chinese individuals by conducting a genome-wide association study (GWAS). Bone mineral density (BMD) of postmenopausal Chinese women was assessed. Participants with T-score < −2.5 standard deviations (n = 341) were recruited and divided into a discovery group (n = 150) and a replication group (n = 191). GWAS was performed, with T-score as the quantitative trait, using linear regression. Our results revealed that an SNP cluster upstream of RREB1 showed a trend of association with BMD in Chinese PMO patients. The leading SNP of the cluster was rs475011 (p combined = 1.15 × 10−6, beta = 0.51), which is a splicing quantitative trait locus (sQTL) of RREB1. This association was further supported by data from the UK Biobank (UKBB; p = 9.56 × 10−12). The high BMD-associated allele G of rs475011 is related to a high intron excision ratio. This SNP may increase BMD by upregulating mature RREB1 mRNA, based on data from the Genotype-Tissue Expression (GTEx) database. We identified BMD-associated SNPs that regulate RREB1 in Chinese PMO patients. Future functional experiments are needed to further link rs475011, RREB1 , and PMO in Chinese individuals. [ABSTRACT FROM AUTHOR]

Copyright of Osmangazi Journal of Medicine / Osmangazi Tip Dergisi is the property of Eskisehir Osmangazi University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Osmangazi Journal of Medicine / Osmangazi Tip Dergisi is the property of Eskisehir Osmangazi University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Postmenopausal osteoporosis (PMO) is the most common bone disorder in elderly Chinese women. Although genetic factors have been shown to have a pivotal role in PMO, studies on genetic loci associated with PMO in Chinese individuals are still lacking. We aimed to identify SNPs that contribute to PMO in Chinese individuals by conducting a genome-wide association study (GWAS). Bone mineral density (BMD) of postmenopausal Chinese women was assessed. Participants with T-score < −2.5 standard deviations (n = 341) were recruited and divided into a discovery group (n = 150) and a replication group (n = 191). GWAS was performed, with T-score as the quantitative trait, using linear regression. Our results revealed that an SNP cluster upstream of RREB1 showed a trend of association with BMD in Chinese PMO patients. The leading SNP of the cluster was rs475011 (pcombined = 1.15 × 10−6, beta = 0.51), which is a splicing quantitative trait locus (sQTL) of RREB1. This association was further supported by data from the UK Biobank (UKBB; p = 9.56 × 10−12). The high BMD-associated allele G of rs475011 is related to a high intron excision ratio. This SNP may increase BMD by upregulating mature RREB1 mRNA, based on data from the Genotype-Tissue Expression (GTEx) database. We identified BMD-associated SNPs that regulate RREB1 in Chinese PMO patients. Future functional experiments are needed to further link rs475011, RREB1, and PMO in Chinese individuals.

Ras-responsive element-binding protein 1 (Rreb1) is a zinc-finger transcription factor acting downstream of RAS signaling. Rreb1 has been implicated in cancer and Noonan-like RASopathies. However, little is known about its role in mammalian non-disease states. Here, we show that Rreb1 is essential for mouse embryonic development. Loss of Rreb1 led to a reduction in the expression of vasculogenic factors, cardiovascular defects, and embryonic lethality. During gastrulation, the absence of Rreb1 also resulted in the upregulation of cytoskeleton-associated genes, a change in the organization of F-ACTIN and adherens junctions within the pluripotent epiblast, and perturbed epithelial architecture. Moreover, Rreb1 mutant cells ectopically exited the epiblast epithelium through the underlying basement membrane, paralleling cell behaviors observed during metastasis. Thus, disentangling the function of Rreb1 in development should shed light on its role in cancer and other diseases involving loss of epithelial integrity.

Ectomesenchymal chondromyxoid tumor is a rare neoplasm of uncertain histogenesis that typically occurs in the anterior dorsal tongue. Recent reports in the literature have described rare examples of gingival, palatal and tonsillar lesions. Histologically, ectomesenchymal chondromyxoid tumors are typically well-circumscribed, lacking overtly aggressive features. Herein we report a tumor arising in the right mandible that is morphologically and molecularly consistent with ectomesenchymal chondromyxoid tumor. This case furthers awareness of the extra-glossal distribution of this neoplasm; moreover, it suggests that a subset of these tumors have the potential for locally aggressive behaviour. [ABSTRACT FROM AUTHOR]

Small non-coding RNAs, microRNAs (miRNA), inhibit the translation or accelerate the degradation of message RNA (mRNA) by targeting the 3'-untranslated region (3'-UTR) in regulating growth and survival through gene suppression. Deregulated miRNA expression contributes to disease progression in several cancers types, including pancreatic cancers (PaCa). PaCa tissues and cells exhibit decreased miRNA, elevated cyclooxygenase (COX)-2 and increased prostaglandin E2 (PGE2) resulting in increased cancer growth and metastases. Human PaCa cell lines were used to demonstrate that restoration of miRNA-143 (miR-143) regulates COX-2 and inhibits cell proliferation. miR-143 were detected at fold levels of 0.41 ± 0.06 in AsPC-1, 0.20 ± 0.05 in Capan-2 and 0.10 ± 0.02 in MIA PaCa-2. miR-143 was not detected in BxPC-3, HPAF-II and Panc-1 which correlated with elevated mitogen-activated kinase (MAPK) and MAPK kinase (MEK) activation. Treatment with 10 μM of MEK inhibitor U0126 or PD98059 increased miR-143, respectively, by 187 ± 18 and 152 ± 26-fold in BxPC-3 and 182 ± 7 and 136 ± 9-fold in HPAF-II. miR-143 transfection diminished COX-2 mRNA stability at 60 min by 2.6 ± 0.3-fold in BxPC-3 and 2.5 ± 0.2-fold in HPAF-II. COX-2 expression and cellular proliferation in BxPC-3 and HPAF-II inversely correlated with increasing miR-143. PGE2 levels decreased by 39.3 ± 5.0% in BxPC-3 and 48.0 ± 3.0% in HPAF-II transfected with miR-143. Restoration of miR-143 in PaCa cells suppressed of COX-2, PGE2, cellular proliferation and MEK/MAPK activation, implicating this pathway in regulating miR-143 expression.

Aims: Ectomesenchymal chondromyxoid tumour (ECT) is a rare benign intraoral tumour which almost exclusively presents as a small mass of the anterior dorsal tongue. Recently, the RREB1–MRTFB (previously known as MKL2) fusion gene has been identified in 90% of ECTs, all located in the tongue, emphasising its genetic distinctiveness. Here, we report two mesenchymal tumours involving the superior mediastinum of adult women with RREB1–MRTFB fusions. Methods and results: Both tumours presented as well‐circumscribed paravertebral masses that were clinically suspected to be schwannoma. After fragmented resection, recurrence was not observed at 27 and 18 months. Although tumours were originally unclassifiable, next‐generation sequencing detected identical RREB1 (exon 8)–MRTFB (exon 11) fusion transcripts, which were validated by reverse transcriptase–polymerase chain reaction, Sanger sequencing, and fluorescence in‐situ hybridisation. Both tumours shared hyalinised areas with round cells embedded in a cord or reticular manner. The tumour cells showed mild nuclear atypia of possible degenerative type with very low mitotic activity, and were at least focally positive for S100, glial fibrillary acidic protein, smooth muscle actin and epithelial membrane antigen. Overall, these findings suggest that they may represent previously undescribed extra‐glossal ECT involving the mediastinum. However, the histology was not classic for ECT, because that in case 2 was predominated by storiform growth of spindle cells, whereas the tumour in case 1 lacked myxoid change. Conclusions: We have provided the first evidence that RREB1–MRTFB fusion is not limited to tumours in the head region, and whether such tumours represent extra‐glossal ECTs requires further research. [ABSTRACT FROM AUTHOR]

The RREB1::MRTFB (former RREB1::MKL2) fusion characterizes ectomesenchymal chondromyxoid tumors (EMCMT) of the tongue. Only five molecularly confirmed extra-glossal EMCMT cases have been reported recently; all occurring at head and neck or mediastinal sites. We herein describe five new cases including the first two extracranial/extrathoracic cases. The tumors occurred in three male and two female patients with an age ranging from 18 to 61 years (median, 28). Three tumors were located in the head and neck (jaw, parapharyngeal space, and nasopharyngeal wall) and two in the soft tissue (inguinal and presacral). The tumor size ranged from 3.3 to 20 cm (median, 7). Treatment was surgical without adjuvant treatment in all cases. Two cases were disease-free at 5 and 17 months; other cases were lost to follow-up. Histologically, the soft tissue cases shared a predominant fibromyxoid appearance, but with variable cytoarchitectural pattern (cellular perineurioma-like whorls and storiform pattern in one case and large polygonal granular cells embedded within a chondromyxoid stroma in the other). Two tumors (inguinal and parapharyngeal) showed spindled to ovoid and round cells with a moderately to highly cellular nondescript pattern. One sinonasal tumor closely mimicked nasal chondromesenchymal hamartoma (NCMH). Mitotic activity was low (0-5 mitoses/10 hpfs). Immunohistochemical findings were heterogeneous with variable expression of S100 (2/5), EMA (2/3), CD34 (1/4), desmin (1/4), and GFAP (1/3). Targeted RNA sequencing revealed the same RREB1::MRTFB fusion in all cases, with exon 8 of RREB1 being fused to exon 11 of MRTFB. This study expands the topographic spectrum of RREB1::MRTFB fusion-positive mesenchymal neoplasms, highlighting a significant morphological and phenotypic diversity. Overall, RREB1::MRTFB-rearranged neoplasms seem to fall into two subcategories: tumors with lobulated, chondroid, or myxochondroid epithelioid morphology (Cases 2 and 3) and those with more undifferentiated hypercellular spindle cell phenotype (Cases 1, 4, and 5). Involvement of extracranial/extrathoracic sites and the NCMH-like pattern are novel. The biology of these likely indolent or benign tumors remains to be verified in the future., (© 2022 The Authors. Genes, Chromosomes and Cancer published by Wiley Periodicals LLC.)

Background: As a chemoprevention agent, crocin effectively decreases the risk of human cancers, including colorectal cancer (CRC). However, the mechanism underlying the anti-cancer effects of crocin is not entirely explained. Considering that in this study, we investigated the crocin effect on miR-143/145 and related signaling pathways in CRC cells., Methods: HCT-116 and HT-29 CRC cells were treated with different concentrations of crocin and then were subjected to MTT and qRT-PCR assays to investigate cell viability and miR-143/miR-145, KRAS , and RREB1 expression, respectively. Also, western blotting was performed to evaluate gene expression at protein levels., Results: Our results showed that treating CRC cells with crocin decreases cell viability by upregulating miR-143/145 expression and reducing KRAS and RREB1 expression dose-dependently. These effects on gene expression in CRC cells were reversed by removing crocin from the media after 48 h. Furthermore, western blotting results exhibited that crocin significantly reduced the protein expression of KRAS and RREB1. Also, it was found that treatment of CRC cells by crocin led to the inactivation of AKT by decreasing its phosphorylation., Conclusions: This study suggests that crocin may inhibit CRC cell proliferation by modulating KRAS, REEB1, and AKT signaling pathways mediated through miR-143/145 upregulation., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Cleft palate is one of the major congenital craniofacial birth defects. The etiology underlying the pathogenesis of cleft palate has yet to be fully elucidated. Dissociation of the medial edge epithelium (MEE) at the contacting region of palatal shelves and subsequent migration or apoptosis of MEE cells is required for proper MEE removal. Ras-responsive element-binding protein 1 (RREB1), a RAS transcriptional effector, has recently been shown to play a crucial role in developmental epithelial-mesenchymal transition (EMT), in which loss of epithelial characteristics is an initial step, during mid-gastrulation of embryonic development. Interestingly, the involvement of RREB1 in cleft palate has been indicated in humans. Here, we demonstrated that pan-Ras inhibitor prevents the dissociation of MEE during murine palatal fusion. Rreb1 is expressed in the palatal epithelium during palatal fusion, and knockdown of Rreb1 in palatal organ culture resulted in palatal fusion defects by inhibiting the dissociation of MEE cells. Our present findings provide evidence that RREB1-mediated Ras signaling is required during palatal fusion. Aberrant RREB1-mediated Ras signaling might be involved in the pathogenesis of cleft palate., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)

Thyroid cancer (TC) is the most common endocrine malignancy. Medullary thyroid carcinoma (MTC) is derived from parathyroid follicle cells (C cells) secrete calcitonin, accounting for approximately 5-10% of all thyroid cancers. The malignancy is between differentiated and undifferentiated thyroid cancer and undifferentiated thyroid cancer and has a relatively poor prognosis. In MTC tumor cells, RREB1 regulates the differentiation of parathyroid cells via RAS-Raf-1-ELK3 signaling and induce calcitonin secretion. Therefore, it is easy to induce parathyroid parafollicular cells canceration and medullary thyroid carcinoma. Here, we investigated the correlation between RREB1, RAS-Raf-1-ELK3 signaling pathway and medullary thyroid carcinoma with various phases. Our results suggest that RREB1 promotes parafollicular carcinoma through the Ras-Raf1-elk3 signaling pathway, providing a rationale to further investigate the role of RREB1 in parafollicular carcinoma. It provides theoretical guidance for the clinical treatment of medullary thyroid cancer.

Gastric cancer (GC) is the most common gastrointestinal malignancy worldwide. However, the molecular mechanisms of the progression of GC are not fully understood. Ras-responsive element binding protein 1 (RREB1) is an oncogene in many types of cancer that is involved in various biological processes, such as DNA damage repair, cell growth and proliferation, cell differentiation, fat development, and fasting glucose balance. In this study, we demonstrate the role of RREB1 in gastric cancer. First, by immunohistochemistry staining (IHC) and bioinformatics analysis, we demonstrated the expression of RREB1 in gastric cancer and paired normal gastric tissues. Then, we established RREB1 overexpression and knockdown cell lines via lentiviral transfection and detected cell proliferation by using MTT, colony-forming, cell cycle and apoptosis assays in vitro. We demonstrated the effect of RREB1 on cell proliferation in vivo by using a subcutaneous xenograft tumor model in nude mice. Finally, by using Western blotting and IHC, we demonstrated the possible mechanism by which RREB1 affects cell proliferation. The IHC and bioinformatics analyses demonstrated that RREB1 was highly expressed in gastric cancer and showed that RREB1-expressing patients had a larger tumor size and more lymphovascular invasion than RREB1-negative patients. Knockdown of RREB1 inhibited cell proliferation in vivo and in vitro. Knockdown of RREB1 enhanced p16 expression in vivo and in vitro, and p16 expression was negatively related to RREB1 in gastric cancer tissue. RREB1 was highly expressed in gastric cancer, and knockdown of RREB1 inhibited cell proliferation via enhanced p16 expression.

Biphenotypic sinonasal sarcoma (BSNS) is a rare, low grade spindle cell sarcoma, recently recognized in the WHO classification of head and neck tumors, which is characterized by a dual myogenic and neural differentiation and recurrent gene fusions, often involving PAX3-MAML3, and less commonly PAX3 fusions with other partners such as NCOA1, NCOA2, or WWTR1. Yet, in about 4% of tumors no gene rearrangements are identified. Herein, we describe a RREB1-MKL2 fusion in a BSNS lesion occurring in a 73-year-old female patient with a right maxillo-ethmoidal angle lesion. The polypoid, moderately cellular tumor with infiltrative submucosal growth was composed of fascicles of relatively bland spindle cells embedded in a loose collagenous matrix. The tumor cells showed moderate amounts of eosinophilic cytoplasm with indistinct borders and uniform, pale, ovoid to slender nuclei. The slowly proliferating neoplastic cells co-expressed smooth muscle actin and S100, and showed focal nuclear positivity for ß-catenin, while lacking staining for cytokeratins, desmin, myogenin, caldesmon, glial fibrillary acid protein, and SOX-10. Molecular analysis by targeted RNA-based next-generation sequencing identified an in-frame fusion between exon 8 of RREB1 and exon 11 of MKL2, a genetic event that was reported to be a molecular hallmark of ectomesenchymal chondromyxoid tumor. Gene rearrangements in both genes were independently verified by fluorescence in situ hybridization (FISH). To evaluate its recurrent potential an additional group of 15 fusion negative BSNS were tested for abnormalities in RREB1 and MKL2 genes by FISH, but no additional positive cases were identified., (© 2021 The Authors. Genes, Chromosomes and Cancer published by Wiley Periodicals LLC.)

Ras-responsive element-binding protein 1 (Rreb1) is a zinc-finger transcription factor acting downstream of RAS signaling. Rreb1 has been implicated in cancer and Noonan-like RASopathies. However, little is known about its role in mammalian non-disease states. Here, we show that Rreb1 is essential for mouse embryonic development. Loss of Rreb1 led to a reduction in the expression of vasculogenic factors, cardiovascular defects, and embryonic lethality. During gastrulation, the absence of Rreb1 also resulted in the upregulation of cytoskeleton-associated genes, a change in the organization of F-ACTIN and adherens junctions within the pluripotent epiblast, and perturbed epithelial architecture. Moreover, Rreb1 mutant cells ectopically exited the epiblast epithelium through the underlying basement membrane, paralleling cell behaviors observed during metastasis. Thus, disentangling the function of Rreb1 in development should shed light on its role in cancer and other diseases involving loss of epithelial integrity., Competing Interests: SM, JS, JN, JM, AH No competing interests declared, (© 2021, Morgani et al.)

The Ras-responsive element binding protein 1(RREB1) is a member of zinc finger transcription factors, which is widely involved in biological processes including cell proliferation, transcriptional regulation and DNA damage repair. New findings reveal RREB1 functions as both transcriptional repressors and transcriptional activators for transcriptional regulation of target genes. The activation of RREB1 is regulated by MAPK pathway. We have summarized the target genes of RREB1 and discussed RREB1 roles in the cancer development. In addition, increasing evidences suggest that RREB1 is a potential risk gene for type 2 diabetes and obesity. We also review the current clinical application of RREB1 as a biomarker for melanoma detection. In conclusion, RREB1 is a promising diagnostic biomarker or new drug target for cancers and metabolic diseases., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

An increasing number of sarcomas displaying a primitive, monomorphic spindle cell phenotype have been shown to harbor recurrent gene fusions, including biphenotypic sinonasal sarcoma (SNS). Occurring in the sinonasal area of middle-aged patients, SNS is a locally aggressive tumor harboring in 90% of cases recurrent gene fusions involving the PAX3 gene, in which the chimeric transcription factor induces an aberrant dual myogenic and neural phenotype. Here, we report an unusual oropharyngeal monomorphic spindle cell sarcoma in a 53-year-old man that revealed a novel RREB1-MKL2 gene fusion by RNA sequencing with the Illumina TruSight RNA Fusion Panel. The gene fusion was validated by RT-PCR. Although the tumor location is unusual (but head and neck seated), most of the other clinical, morphologic, immunophenotypic (focal combined expression of S100 protein, SMA, desmin, and myogenin) and oncogenic data suggest that this biphenotypic "oropharyngeal" sarcoma is closely related to the biphenotypic SNS spectrum. Notably, the RREB1-MKL2 chimeric transcription factor encoded by this fusion gene produced an increase in MKL2 expression, which regulates both neural and myogenic differentiation, mimicking the crucial role of PAX3 reported in SNS oncogenesis. NGS and especially RNA sequencing may be used to identify new candidate fusion oncogenes in soft tissue tumors, which would help in updating the existing classification. In turn, this would lead to better therapeutic management of patients., (© 2017 Wiley Periodicals, Inc.)

Pancreatic cancer (adenocarcinoma) remains a deadly untreatable cancer with no effective early detection procedure. Little is known concerning the factors involved in the development of pancreatic malignancy, which impedes advancements in its treatment and detection. Altered cellular zinc has been implicated in several cancers. Recent studies provide evidence that zinc and zinc transporters are important factors in pancreatic cancer. This review discusses the current information relating to the status of zinc and zinc transporters in human pancreatic adenocarcinoma. Relationships of the physiology and biochemistry of zinc in mammalian cells are presented, which should be applied to the conduct, interpretation, and translational application of human studies and experimental models. Evidence from human pancreatic tissue studies supports a new concept of the role of zinc in the development of pancreatic adenocarcinoma. The zinc level of the normal ductal and acinar epithelium is markedly decreased in the development of the malignant cells and the premalignant PanIN cells. ZIP3 is identified as the likely zinc uptake transporter, which is down regulated concurrently with the loss of zinc. Ras responsive binding protein (RREB1) is identified as the possible transcription factor involved in the silencing of ZIP3 expression. The evidence supports the current views of transdifferentiation of PanIN epithelium to ductal adenocarcinoma, and the possibility that acinar epithelial dedifferentiation might be a source of premalignant cells. These zinc-associated events occur early in oncogenesis to protect the malignant cells from the cytotoxic effects of zinc levels that exist in the normal cells. Hopefully, this presentation will stimulate interest in and support for much needed research into the implications of zinc and zinc transporters as important events in pancreatic carcinogenesis. The potential exists for the RREB1-ZIP3-zinc concept and/or other implications of zinc as new approaches for the development of effective treatment and for diagnostic biomarkers for pancreatic cancer.