Characterization of age-associated gene expression changes in mouse sweat glands

Evaporation of sweat on the skin surface is the major mechanism for dissipating heat in humans. The secretory capacity of sweat glands (SWGs) declines during aging, leading to heat intolerance in the elderly, but the mechanisms responsible for this decline are poorly understood. We investigated the molecular changes accompanying SWG aging in mice, where sweat tests confirmed a significant reduction of active SWGs in old mice relative to young mice. We first identified SWG-enriched mRNAs by comparing the skin transcriptome of Eda mutant Tabby male mice, which lack SWGs, with that of wild-type control mice by RNA-sequencing analysis. This comparison revealed 171 mRNAs enriched in SWGs, including 47 mRNAs encoding 'core secretory' proteins such as transcription factors, ion channels, ion transporters, and trans-synaptic signaling proteins. Among these, 28 SWG-enriched mRNAs showed significantly altered abundance in the aged male footpad skin, and 11 of them, including Foxa1, Best2, Chrm3, and Foxc1 mRNAs, were found in the 'core secretory' category. Consistent with the changes in mRNA expression levels, immunohistology revealed that higher numbers of secretory cells from old SWGs express the transcription factor FOXC1, the protein product of Foxc1 mRNA. In sum, our study identified mRNAs enriched in SWGs, including those that encode core secretory proteins, and altered abundance of these mRNAs and proteins with aging in mouse SWGs.

Exploring the Genetic Landscape of Childhood Glaucoma

Childhood glaucoma, a significant cause of global blindness, represents a heterogeneous group of disorders categorized into primary or secondary forms. Primary childhood glaucoma stands as the most prevalent subtype, comprising primary congenital glaucoma (PCG) and juvenile open-angle glaucoma (JOAG). Presently, multiple genes are implicated in inherited forms of primary childhood glaucoma. This comprehensive review delves into genetic investigations into primary childhood glaucoma, with a focus on identifying causative genes, understanding their inheritance patterns, exploring essential biological pathways in disease pathogenesis, and utilizing animal models to study these mechanisms. Specifically, attention is directed towards genes such as CYP1B1 (cytochrome P450 family 1 subfamily B member 1), LTBP2 (latent transforming growth factor beta binding protein 2), TEK (TEK receptor tyrosine kinase), ANGPT1 (angiopoietin 1), and FOXC1 (forkhead box C1), all associated with PCG; and MYOC (myocilin), associated with JOAG. Through exploring these genetic factors, this review aims to deepen our understanding of the intricate pathogenesis of primary childhood glaucoma, thereby facilitating the development of enhanced diagnostic and therapeutic strategies.

Variants in FOXC1 and FOXC2 identified in patients with conotruncal heart defects

Conotruncal heart defects (CTD), subtypes of congenital heart disease, result from abnormal cardiac outflow tract development (OFT). FOXC1 and FOXC2 are closely related members of the forkhead transcription factor family and play essential roles in the development of OFT. We confirmed their expression pattern in mouse and human embryos, identifying four variants in FOXC1 and three in FOXC2 by screening these two genes in 605 patients with sporadic CTD. Western blot demonstrated expression levels, while Dual-luciferase reporter assay revealed affected transcriptional abilities for TBX1 enhancer in two FOXC1 variants and three FOXC2 variants. This might result from the altered DNA-binding abilities of mutant proteins. These results indicate that functionally impaired FOXC1 and FOXC2 variants may contribute to the occurrence of CTD.

Research progress on the regulatory mechanisms of FOXC1 expression in cancers and its role in drug resistance

The Forkhead box C1 (FOXC1) transcription factor is an important member of the FOX family. After initially being identified in triple-negative breast cancer (TNBC) with significant oncogenic function, FOXC1 was subsequently demonstrated to be involved in the development of more than 16 types of cancers. In recent years, increasing studies have focused on the deregulatory mechanisms of FOXC1 expression and revealed that FOXC1 expression was regulated at multiple levels including transcriptional regulation, post-transcription regulation and post-translational modification. Moreover, dysregulation of FOXC1 is also implicated in drug resistance in various types of cancer, especially in breast cancer, which further emphasizes the translational and clinical significance of FOXC1 as a therapeutic target in cancer treatment. This review summarizes recent findings on mechanisms of FOXC1 dysregulation in cancers and its role in chemoresistance, which will help to better understand the oncogenic role of FOXC1, overcome FOXC1-mediated drug resistance and develop targeted therapy for FOXC1 in cancers.

Structural Variant Disrupting the Expression of the Remote FOXC1 Gene in a Patient with Syndromic Complex Microphthalmia

Ocular malformations (OMs) arise from early defects during embryonic eye development. Despite the identification of over 100 genes linked to this heterogeneous group of disorders, the genetic cause remains unknown for half of the individuals following Whole-Exome Sequencing. Diagnosis procedures are further hampered by the difficulty of studying samples from clinically relevant tissue, which is one of the main obstacles in OMs. Whole-Genome Sequencing (WGS) to screen for non-coding regions and structural variants may unveil new diagnoses for OM individuals. In this study, we report a patient exhibiting a syndromic OM with a de novo 3.15 Mb inversion in the 6p25 region identified by WGS. This balanced structural variant was located 100 kb away from the FOXC1 gene, previously associated with ocular defects in the literature. We hypothesized that the inversion disrupts the topologically associating domain of FOXC1 and impairs the expression of the gene. Using a new type of samples to study transcripts, we were able to show that the patient presented monoallelic expression of FOXC1 in conjunctival cells, consistent with the abolition of the expression of the inverted allele. This report underscores the importance of investigating structural variants, even in non-coding regions, in individuals affected by ocular malformations.

FOXC1 Promotes Osteoblastic Differentiation of Bone Marrow Mesenchymal Stem Cells via the Dnmt3b/CXCL12 Axis

Bone defects have remained a clinical problem in current orthopedics. Bone marrow mesenchymal stem cells (BM-MSCs) with multi-directional differentiation ability have become a research hotspot for repairing bone defects. In vitro and in vivo models were constructed, respectively. Alkaline phosphatase (ALP) staining and alizarin red staining were performed to detect osteogenic differentiation ability. Western blotting (WB) was used to detect the expression of osteogenic differentiation-related proteins. Serum inflammatory cytokine levels were detected by ELISA. Fracture recovery was evaluated by HE staining. The binding relationship between FOXC1 and Dnmt3b was verified by dual-luciferase reporter assay. The relationship between Dnmt3b and CXCL12 was explored by MSP and ChIP assays. FOXC1 overexpression promoted calcium nodule formation, upregulated osteogenic differentiation-related protein expression, promoted osteogenic differentiation, and decreased inflammatory factor levels in BM-MSCs, and promoted callus formation, upregulated osteogenic differentiation-related protein expression, and downregulated CXCL12 expression in the mouse model. Furthermore, FOXC1 targeted Dnmt3b, with Dnmt3b knockdown decreasing calcium nodule formation and downregulating osteogenic differentiation-related protein expression. Additionally, inhibiting Dnmt3b expression upregulated CXCL12 protein expression and inhibited CXCL12 methylation. Dnmt3b could be binded to CXCL12. CXCL12 overexpression attenuated the effects of FOXC1 overexpression and inhibited BM-MSCs osteogenic differentiation. This study confirmed that the FOXC1-mediated regulation of the Dnmt3b/CXCL12 axis had positive effects on the osteogenic differentiation of BM-MSCs.

Isorhynchophylline attenuates proliferation and migration of synovial fibroblasts via the FOXC1/β-catenin axis

Rheumatoid arthritis (RA) is a common type of chronic inflammatory disease. Elucidating the mechanism of fibroblast-like synovial (FLS) as a pathologic factor in RA may address the urgent medical requirement for the treatment of RA. Isorhynchophylline (IRN) is a tetracyclic hydroxyindole alkaloid isolated from uncinaria, which has multiple biological activities and affects the progression of osteoarthritis. However, the role of IRN in rheumatoid arthritis remains unclear. Herein, our study aimed to elucidate the potential effect of IRN on RA and reveal its mechanism. Human FLS cell line MH7A cells were stimulated with TNF-α for 24 h to construct a cell model. CCK-8, Edu, wound healing, as well as transwell assays were conducted to detect the effects of IRN on cell proliferation and motility. ELISA and Immunoblot assays were further performed to detect the production of pro-inflammatory factors and the expression levels of MMPs. Immunoblot and Immunostaining assays were conducted to uncover the mechanism. ELISA, H&E staining, and Immunoblot assays were used to confirm the effects of IRN on RA in a CIA rat model. We revealed that IRN restrained TNF-α-stimulated MH7A cell proliferation and motility. In addition, IRN blocked the production of pro-inflammatory factors and MMPs in TNF-α-stimulated-MH7A cells. We further found that IRN restrained FOXC1/β-catenin axis, and improved MH7A cell proliferation as well as migration via the FOXC1/β-catenin axis. IRN restores CIA by inhibiting pro-inflammatory cytokines in synovial tissues. In summary, IRN attenuates proliferation and migration of FLS in RA via the FOXC1 mediated β-catenin axis.

Icaritin inhibits endometrial carcinoma cells by suppressing O-GlcNAcylation of FOXC1

BACKGROUND

Icaritin has a wide range of pharmacological activities, including significant an-titumor activity. However, the mechanism of action of icaritin in endometrial cancer (UCEC) remains unknown. FOX proteins are a highly conserved transcription factor superfamily that play important roles in epithelial cell differentiation, tumor metastasis, angiogenesis, and cell cycle regulation. FOXC1 is an important member of the FOX protein family. FOXC1 is aberrantly expressed in endometrial cancer and may play a role in the migration and invasion of endometrial cancer; however, its mechanism of action has not yet been reported. O-GlcNAc glycosylation is a common post-translational modification. In endometrial cancer, high levels of O-GlcNAcylation promote cell proliferation, migration, and invasion. Cancer development is often accompanied by O-GlcNAc modification of proteins; however, O-GlcNAc modification of the transcription factor FOXC1 has not been reported to date.

PURPOSE

To investigate the inhibitory effects of icaritin on RL95-2 and Ishikawa endometrial cancer cells in vitro and in vivo and to elucidate the possible molecular mechanisms.

METHODS/STUDY DESIGN

CCK8, colony formation, migration, and invasion assays were used to determine the inhibitory effects of icaritin on endometrial cancer cells in vitro. Cell cycle regulation was assayed by flow cytometry. Protein levels were measured based on western blotting. The level of FOXC1 expression in endometrial cancer tissues was determined by immunohistochemistry. To assess whether icaritin also has activity in vivo, its effect on tumor xenografts was evaluated.

RESULTS

Immunohistochemical analysis of clinical samples revealed that FOXC1 expression was significantly higher in endometrial cancer tissues than in normal tissues. Downregulation of FOXC1 inhibited the proliferative, colony formation, migration, and invasive abilities of RL95-2 and Ishikawa endometrial cancer cells. Icaritin inhibited the proliferation, colony formation, migration, and invasion of endometrial cancer cells and blocked the cell cycle in S phase. Icaritin affected O-GlcNAc modification of FOXC1 and thus the stability of FOXC1, which subsequently triggered the inhibition of endometrial cancer cell proliferation.

CONCLUSION

The anti-endometrial cancer effect of icaritin is related to the inhibition of abnormal O-GlcNAc modification of FOXC1, which may provide an important theoretical foundation for the use of icaritin against endometrial cancer.

Primary open-angle glaucoma risk prediction with ABCA1 and LOC102723944 variants and their genotype-phenotype correlations in southern Chinese population

Glaucoma is a leading cause of irreversible visual impairment and blindness worldwide. Previous genome-wide association studies have identified caveolin-1 (CAV1), ATP-binding cassette A1 (ABCA1), and forkhead box C1 (FOXC1) loci associated with primary open angle glaucoma (POAG), a major subtype of glaucoma. This study aimed to fine map the association pattern of FOXC1 locus with POAG and determine the correlations of FOXC1, ABCA1, and CAV1 variants with ocular and lipidemic parameters in southern Chinese population. In total, 1291 unrelated Han Chinese subjects were recruited, including 301 high-tension glaucoma (HTG), 126 normal-tension glaucoma (NTG), and 864 control subjects. Twelve variants in FOXC1 locus, and two variants in ABCA1 and CAV1 genes, were genotyped by TaqMan assays. Genetic risk score and genotype-phenotype correlation analyses were conducted. In the FOXC1 locus, LOC102723944 rs6596830, rather than previously reported rs2745572, showed significant association with POAG (P = 8.61 × 10-4, odds ratio (OR) = 0.75) and HTG (P = 3.68 × 10-3, OR = 0.75). ABCA1 rs2487032 was also significantly associated with POAG (P = 3.00 × 10-5, OR = 0.70) and HTG (P = 2.08 × 10-4, OR = 0.70). Joint analysis showed that carriers of homozygous non-protective alleles of ABCA1 rs2487032 and LOC102723944 rs6596830 had 2.99-fold higher risk of POAG (P = 1.27 × 10-3) when compared to those carrying homozygous non-risk alleles. Patients with POAG carrying ABCA1 rs2487032 G allele had higher HDL cholesterol, and those with LOC102723944 rs6596830 A allele had lower LDL. This study revealed individual and joint association of ABCA1 and LOC102723944 variants with POAG in southern Chinese population. Subjects carrying non-protective alleles had increased risk to POAG, and corresponding genotypes would affect the lipid profiles.

Regulation and Function of FOXC1 in Osteoblasts

Estrogens, which bind to estrogen receptor alpha (ERα), are important for proper bone mineral density. When women go through menopause, estrogen levels decrease, and there is a decrease in bone quality, along with an increased risk for fractures. We previously identified an enhancer near FOXC1 as the most significantly enriched binding site for estrogen receptor alpha (ERα) in osteoblasts. FOXC1 is a transcription factor belonging to a large group of proteins known as forkhead box genes and is an important regulator of bone formation. Here, we demonstrate that 17β-estradiol (E2) increases the mRNA and protein levels of FOXC1 in primary mouse and human osteoblasts. GATA4 is a pioneer factor for ERα and it is also recruited to enhancers near Foxc1. Knockdown of Gata4 in mouse osteoblasts in vitro decreases Foxc1 expression as does knockout of Gata4 in vivo. Functionally, GATA4 and FOXC1 interact and regulate osteoblast proteins such as RUNX2, as demonstrated by ChIP-reChIP and luciferase assays. The most enriched motif in GATA4 binding sites from ChIP-seq is for FOXC1, supporting the notion that GATA4 and FOXC1 cooperate in regulating osteoblast differentiation. Together, these data demonstrate the interactions of the transcription factors ERα, GATA4, and FOXC1 to regulate each other's expression and other osteoblast differentiation genes.

Single-cell RNA sequencing reveals tumor heterogeneity within salivary gland pleomorphic adenoma: A preliminary study

BACKGROUND

Salivary gland pleomorphic adenoma (SPA) is a common neoplasm of salivary glands that displays remarkable histological diversity. Previous studies have demonstrated the involvement of gene rearrangements and cytoskeleton-remodeling-related myoepithelial cells in SPA tumorigenesis. Cytoskeleton remodeling is necessary for epithelial-mesenchymal transition (EMT), a key process in tumor progression. However, the heterogeneity of tumor cells and cytoskeleton remodeling in SPA has not been extensively investigated.

METHODS

An analysis of single-cell RNA sequencing (scRNA-seq) was performed on 27 810 cells from two donors with SPA. Bioinformatic tools were used to assess differentially expressed genes, cell trajectories, and intercellular communications. Immunohistochemistry and double immunofluorescence staining were used to demonstrate FOXC1 and MYLK expression in SPA tissues.

RESULTS

Our analysis revealed five distinct cell subtypes within the tumor cells of SPA, indicating a high level of intra-lesional heterogeneity. Cytoskeleton-remodeling-related genes were highly enriched in subtype 3 of the tumor cells, which showed a close interaction with mesenchymal cells. We found that tumoral FOXC1 expression was closely related to MYLK expression in the tumor cells of SPA.

CONCLUSION

Tumor cells enriched with cytoskeleton-remodeling-related genes play a crucial role in SPA development, and FOXC1 may partially regulate this process.

FOXC1 and FOXC2 maintain mitral valve endothelial cell junctions, extracellular matrix, and lymphatic vessels to prevent myxomatous degeneration

Background

Mitral valve (MV) disease including myxomatous degeneration is the most common form of valvular heart disease with an age-dependent frequency. Genetic evidence indicates mutations of the transcription factor FOXC1 are associated with MV defects, including mitral valve regurgitation. In this study, we sought to determine whether murine Foxc1 and its closely related factor, Foxc2, are required in valvular endothelial cells (VECs) for the maintenance of MV leaflets, including VEC junctions and the stratified trilaminar extracellular matrix (ECM).

Methods

Adult mice carrying tamoxifen-inducible, endothelial cell (EC)-specific, compound Foxc1;Foxc2 mutations (i.e., EC-Foxc-DKO mice) were used to study the function of Foxc1 and Foxc2 in the maintenance of mitral valves. The EC-mutations of Foxc1/c2 were induced at 7 - 8 weeks of age by tamoxifen treatment, and abnormalities in the MVs of EC-Foxc-DKO mice were assessed via whole-mount immunostaining, immunohistochemistry, and Movat pentachrome/Masson's Trichrome staining.

Results

EC-deletions of Foxc1 and Foxc2 in mice resulted in abnormally extended and thicker mitral valves by causing defects in regulation of ECM organization with increased proteoglycan and decreased collagen. Notably, reticular adherens junctions were found in VECs of control MV leaflets, and these reticular structures were severely disrupted in EC-Foxc1/c2 mutant mice. PROX1, a key regulator in a subset of VECs on the fibrosa side of MVs, was downregulated in EC-Foxc1/c2 mutant VECs. Furthermore, we determined the precise location of lymphatic vessels in murine MVs, and these lymphatic vessels were aberrantly expanded in EC-Foxc1/c2 mutant mitral valves.

Conclusions

Our results indicate that Foxc1 and Foxc2 are required for maintaining the integrity of the MV, including VEC junctions, ECM organization, and lymphatic vessels to prevent myxomatous mitral valve degeneration.

Case report: Extending the spectrum of clinical and molecular findings in FOXC1 haploinsufficiency syndrome

FOXC1 is a ubiquitously expressed forkhead transcription factor that plays a critical role during early development. Germline pathogenic variants in FOXC1 are associated with anterior segment dysgenesis and Axenfeld-Rieger syndrome (ARS, #602482), an autosomal dominant condition with ophthalmologic anterior segment abnormalities, high risk for glaucoma and extraocular findings including distinctive facial features, as well as dental, skeletal, audiologic, and cardiac anomalies. De Hauwere syndrome is an ultrarare condition previously associated with 6p microdeletions and characterized by anterior segment dysgenesis, joint instability, short stature, hydrocephalus, and skeletal abnormalities. Here, we report clinical findings of two unrelated adult females with FOXC1 haploinsufficiency who have ARS and skeletal abnormalities. Final molecular diagnoses of both patients were achieved using genome sequencing. Patient 1 had a complex rearrangement involving a 4.9 kB deletion including FOXC1 coding region (Hg19; chr6:1,609,721-1,614,709), as well as a 7 MB inversion (Hg19; chr6:1,614,710-8,676,899) and a second deletion of 7.1 kb (Hg19; chr6:8,676,900-8,684,071). Patient 2 had a heterozygous single nucleotide deletion, resulting in a frameshift and a premature stop codon in FOXC1 (NM_001453.3): c.467del, p.(Pro156Argfs*25). Both individuals had moderate short stature, skeletal abnormalities, anterior segment dysgenesis, glaucoma, joint laxity, pes planovalgus, dental anomalies, hydrocephalus, distinctive facial features, and normal intelligence. Skeletal surveys revealed dolichospondyly, epiphyseal hypoplasia of femoral and humeral heads, dolichocephaly with frontal bossin gand gracile long bones. We conclude that haploinsufficiency of FOXC1 causes ARS and a broad spectrum of symptoms with variable expressivity that at its most severe end also includes a phenotype overlapping with De Hauwere syndrome.

Spectrum of white matter abnormalities associated with FOXC1-related disorders in two unrelated cases

The purpose of this study is to document the wide spectrum of white matter abnormalities associated with FOXC1 pathogenic variants. We report two adult individuals-a 60-year-old individual and a 24-year-old one, presenting with hearing loss, anterior eye segment dysgenesis, and very different severity of cerebral small vessel disease. Molecular testing documented the presence of FOXC1 pathogenic variants in both individuals. Our paper documents the broad spectrum of radiological white matter involvement in adult individuals with FOXC1-related disorders. Mild forms of FOXC1-related small vessel disease, as we observed in individual 2, should be included in the list of genetic mimickers of MS.

Association of variants in the ATXN2 (rs7137828), FOXC1 (rs2745572) and TXNRD2 (rs35934224) genes as risk factors for primary open-angle glaucoma development in a Brazilian cohort

BACKGROUND

Primary open-angle glaucoma (POAG), the world's main cause of irreversible blindness, is an asymptomatic and neurodegenerative disease of multifactorial etiology with ethnic and geographic disparities. Multiethnic genome-wide association studies (GWAS) identified single nucleotide variants (SNVs) in ATXN2, FOXC1, and TXNRD2 loci as risk factors for POAG pathophysiology and/or endophenotypes. The aim of this case-control study was to investigate the association of the variants rs7137828 (ATXN2), rs2745572 (FOXC1), and rs35934224 (TXNRD2), as risk factors for POAG development, additionally to rs7137828 association with glaucoma clinical parameters in a Brazilian cohort from the Southeast and South regions.

METHODS

This investigation comprised 506 cases and 501 controls. Variants rs2745572 and rs35934224 were genotyped through TaqMan® assays and validated by Sanger sequencing. Variant rs7137828 was genotyped exclusively by Sanger sequencing.

RESULTS

The primary research outcome revealed that the variant rs7137828 (ATXN2) was associated with an increased risk for the development of POAG in the presence of the TT genotype compared to the CC genotype (p = 0.006; Odds Ratio [OR] = 1.717; Confidence Interval [CI] 95% = 1.169-2.535). There was no significant association of rs2745572 and rs35934224 genotypes with POAG. The CT genotype of the rs7137828 was associated with the vertical cup-to-disk ratio (VCDR) (p = .023) but not with the age at diagnosis or the mean deviation.

CONCLUSION

Our data indicate the rs7137828 associated with increased risk for the development of POAG and VCDR in a Brazilian cohort. If validated in additional populations, these findings may enable the development of relevant strategies for early diagnosis of glaucoma in the future.

The phenotypic spectrum of terminal and subterminal 6p deletions based on a social media-derived cohort and literature review

BACKGROUND

Terminal 6p deletions are rare, and information on their clinical consequences is scarce, which impedes optimal management and follow-up by clinicians. The parent-driven Chromosome 6 Project collaborates with families of affected children worldwide to better understand the clinical effects of chromosome 6 aberrations and to support clinical guidance. A microarray report is required for participation, and detailed phenotype information is collected directly from parents through a multilingual web-based questionnaire. Information collected from parents is then combined with case data from literature reports. Here, we present our findings on 13 newly identified patients and 46 literature cases with genotypically well-characterised terminal and subterminal 6p deletions. We provide phenotype descriptions for both the whole group and for subgroups based on deletion size and HI gene content.

RESULTS

The total group shared a common phenotype characterised by ocular anterior segment dysgenesis, vision problems, brain malformations, congenital defects of the cardiac septa and valves, mild to moderate hearing impairment, eye movement abnormalities, hypotonia, mild developmental delay and dysmorphic features. These characteristics were observed in all subgroups where FOXC1 was included in the deletion, confirming a dominant role for this gene. Additional characteristics were seen in individuals with terminal deletions exceeding 4.02 Mb, namely complex heart defects, corpus callosum abnormalities, kidney abnormalities and orofacial clefting. Some of these additional features may be related to the loss of other genes in the terminal 6p region, such as RREB1 for the cardiac phenotypes and TUBB2A and TUBB2B for the cerebral phenotypes. In the newly identified patients, we observed previously unreported features including gastrointestinal problems, neurological abnormalities, balance problems and sleep disturbances.

CONCLUSIONS

We present an overview of the phenotypic characteristics observed in terminal and subterminal 6p deletions. This reveals a common phenotype that can be highly attributable to haploinsufficiency of FOXC1, with a possible additional effect of other genes in the 6p25 region. We also delineate the developmental abilities of affected individuals and report on previously unrecognised features, showing the added benefit of collecting information directly from parents. Based on our overview, we provide recommendations for clinical surveillance to support clinicians, patients and families.

Chromosome 6p25 deletion syndrome: A case report and review of ophthalmic features

The 6p25 deletion syndrome is a rare genetic disorder characterized by a wide spectrum of congenital anomalies. Ophthalmic abnormalities appear to be highly associated with the syndrome, although this relationship has not been well characterized to date. We conducted a systematic literature review to highlight the ocular features in patients with this deletion syndrome and describe a 7-month-old female who has a 6.07 MB 6p25.1p25.3 deletion and a 4.25 MB 17q25.3 duplication. Our patient presented with multiple congenital anomalies, including macrocephaly, frontal bossing, low set ears, tent-shaped mouth, saddle nose, flat midface, and hearing impairment. Her ophthalmic features included proptosis, down-slanting palpebral fissures, hypertelorism, nystagmus, bilateral posterior embryotoxon, and decentered and abnormally shaped pupils. A systematic review of the published cases with sufficient clinical eye descriptions included 63 cases with a confirmed 6p25 deletion. The most common eye findings observed were posterior embryotoxon, iris hypoplasia, corectopia, cornea opacity, and glaucoma.

Genotype-phenotype association of PITX2 and FOXC1 in Axenfeld-Rieger syndrome

PITX2 and FOXC1 are the most common pathogenic genes associated with Axenfeld-Rieger syndrome (ARS). In this study, we aimed to explore the variation spectrum of PITX2 and FOXC1 and their associated phenotype based on data from our study and previously reported literatures. Whole exome sequencing was performed on eight probands in our study. Multistep bioinformatic and co-segregation analyses were performed to detect pathogenic variants. Genotype-phenotype correlations of PITX2 and FOXC1 and the differences between them were determined. We detected three variants of FOXC1 and two variants of PITX2 in five unrelated families with ARS. Macular retinoschisis had been observed in AR1 with variant in PITX2 and it is not reported before. Additionally, a review of published literature and our study led to the identification of 593 families with variants of PITX2 or FOXC1, including 316 families with heterozygous variants in FOXC1, 251 families with heterozygous variants in PITX2, 13 families with variants in double genes, seven families with homozygous or compound heterozygous variants in FOXC1, and six families with variants in ADAMTS17, PRDM5, COL4A1 or CYP1B1. Significant differences were observed between the prevalence of missense and in-frame, truncation, and large deletion variants in PITX2 (32.00%, 42.67%, and 25.33%, respectively) and FOXC1 (34.49%, 35.13%, 30.38%, respectively) (p = 1.16E-43). Enrichment and frequency analyses revealed that missense variants were concentrated in the forkhead domain of FOXC1 (76.14%) and homeodomain of PITX2 (87.50%). The percentage of Caucasians with variants in FOXC1 was significantly higher than that of PITX2 (p = 2.00E-2). Significant differences between PITX2 and FOXC1 were observed in glaucoma (p = 3.00E-2), corectopia (p = 3.050E-6), and polycoria (p = 5.21E-08). Additionally, we observed a significant difference in best-corrected visual acuity (BCVA) between FOXC1 and PITX2 (p = 3.80E-2). Among all the family members with PITX2 or FOXC1 variants, the prevalence of systemic abnormalities was significantly higher in PITX2 than in FOXC1 (89.16% vs. 58.77%, p = 5.44E-17). In conclusion, macular retinoschisis as a novel phenotype had been observed in patient with variant in PITX2. Significant differences were detected in phenotypes and genotypes between PITX2 and FOXC1.

Single-cell sequencing reveals activation of core transcription factors in PRC2-deficient malignant peripheral nerve sheath tumor

Loss-of-function mutations in the polycomb repressive complex 2 (PRC2) occur frequently in malignant peripheral nerve sheath tumor, an aggressive sarcoma that arises from NF1-deficient Schwann cells. To define the oncogenic mechanisms underlying PRC2 loss, we use engineered cells that dynamically reassemble a competent PRC2 coupled with single-cell sequencing from clinical samples. We discover a two-pronged oncogenic process: first, PRC2 loss leads to remodeling of the bivalent chromatin and enhancer landscape, causing the upregulation of developmentally regulated transcription factors that enforce a transcriptional circuit serving as the cell’s core vulnerability. Second, PRC2 loss reduces type I interferon signaling and antigen presentation as downstream consequences of hyperactivated Ras and its cross talk with STAT/IRF transcription factors. Mapping of the transcriptional program of these PRC2-deficient tumor cells onto a constructed developmental trajectory of normal Schwann cells reveals that changes induced by PRC2 loss enforce a cellular profile characteristic of a primitive mesenchymal neural crest stem cell.

Zhang et al. provide evidence that PRC2 loss activates cell-fate-determining transcription factors by recruiting active enhancers and dampens type I interferon signaling and antigen presentation through transcriptional cross talk with the hyperactivated Ras. These observations are supported by integrative analysis of single-cell sequencing of patient MPNST samples.

Epigenetic dysregulation in meningiomas

Background

Meningiomas are the most common primary brain tumor. Though typically benign with a low mutational burden, tumors with benign histology may behave aggressively and there are no proven chemotherapies. Although DNA methylation patterns distinguish subgroups of meningiomas and have higher predictive value for tumor behavior than histologic classification, little is known about differences in DNA methylation between meningiomas and surrounding normal dura tissue.

Methods

Whole-exome sequencing and methylation array profiling were performed on 12 dura/meningioma pairs (11 WHO grade I and 1 WHO grade II). Single-nucleotide polymorphism (SNP) genotyping and methylation array profiling were performed on an additional 19 meningiomas (9 WHO grade I, 5 WHO grade II, 4 WHO grade III).

Results

Using multimodal studies of meningioma/dura pairs, we identified 4 distinct DNA methylation patterns. Diffuse DNA hypomethylation of malignant meningiomas readily facilitated their identification from lower-grade tumors by unsupervised clustering. All clusters and 12/12 meningioma-dura pairs exhibited hypomethylation of the gene promoters of a module associated with the craniofacial patterning transcription factor FOXC1 and its upstream lncRNA FOXCUT. Furthermore, we identified an epigenetic continuum of increasing hypermethylation of polycomb repressive complex target promoters with increasing histopathologic grade.

Conclusion

These findings support future investigations of the role of epigenetic dysregulation of FOXC1 and cranial patterning genes in meningioma formation as well as studies of the utility of polycomb inhibitors for the treatment of malignant meningiomas.

Clinical Significance of MAP-7 and FOXC1 in Egyptian Acute Myeloid Leukemia Patients

PURPOSE

The present study aimed to report the clinical correlations and prognostic significance of microtubule-associated protein-1 (MAP-7) and forkhead box transcription factor-C1 (FOXC1) expression in Egyptian patients with newly diagnosed acute myeloid leukemia (AML).

METHODS

The study included 80 adults with newly diagnosed AML. Laboratory investigations included complete blood count, morphological examination of bone marrow aspirate, immunophenotyping, conventional karyotyping and molecular study for fms-like tyrosine kinase 3 (FLT3), nucleophosmin-1 (NPM1) and CCAAT/enhancer binding protein α (CEBPA) mutations. MAP-7 and FOXC1 expressions in bone marrow were determined using RT-PCR. Patients were followed for a median (range) period of 6.4 (1.0-35) months. The study outcomes included treatment response, progression-free survival (PFS) and overall survival (OS).

RESULTS

Patients with low FOXC1 expression had significantly lower mortality rate (60.0 % versus 84.6 %, p=0.021), significantly longer PFS duration and significantly longer OS. No significant differences were noted between MAP7 expression groups regarding treatment response, mortality rate, PFS duration and OS duration. Interestingly, a significant direct correlation was noted between FOXC1 and MAP7 expressions (r=0.25, p=0.027).

CONCLUSIONS

FOXC1 and MAP7 expressions are significantly correlated. High expression of FOXC1 in Egyptian population may be related to shorter OS and PFS.

FOXC1 Binds Enhancers and Promotes Cisplatin Resistance in Bladder Cancer

Simple Summary

In bladder cancer, cisplatin remains the front-line therapy, but drug resistance is common. Previously, we showed that cancer cells can spontaneously convert to an aggressive drug-resistant phenotype without mutational events. In the current work, we explored the epigenetic mechanism behind the conversion to the drug-resistant phenotype. We discovered that drug-resistant cells have differentially accessible enhancers, which are bound by FOXC1, a transcription factor that is overexpressed in these cells. Accordingly, FOXC1 knockout significantly attenuates the emergence of the drug-resistant phenotype and reduces cell survival upon cisplatin treatment. These findings suggest that FOXC1 binding at accessible enhancers promotes cisplatin drug resistance in bladder cancer cells. Therefore, FOXC1 targeting may be a new therapeutic avenue to mitigate cisplatin resistance and improve treatment efficacy in bladder cancer.

Abstract

Chemotherapy resistance is traditionally attributed to DNA mutations that confer a survival advantage under drug selection pressure. However, in bladder cancer and other malignancies, we and others have previously reported that cancer cells can convert spontaneously to an aggressive drug-resistant phenotype without prior drug selection or mutational events. In the current work, we explored possible epigenetic mechanisms behind this phenotypic plasticity. Using Hoechst dye exclusion and flow cytometry, we isolated the aggressive drug-resistant cells and analyzed their chromatin accessibility at regulatory elements. Compared to the rest of the cancer cell population, the aggressive drug-resistant cells exhibited enhancer accessibility changes. In particular, we found that differentially accessible enhancers were enriched for the FOXC1 transcription factor motif, and that FOXC1 was the most significantly overexpressed gene in aggressive drug-resistant cells. ChIP-seq analysis revealed that differentially accessible enhancers in aggressive drug-resistant cells had a higher FOXC1 binding, which regulated the expression of adjacent cancer-relevant genes like ABCB1 and ID3. Accordingly, cisplatin treatment of bladder cancer cells led to an increased FOXC1 expression, which mediated cell survival and conversion to a drug-resistant phenotype. Collectively, these findings suggest that FOXC1 contributes to phenotypic plasticity by binding enhancers and promoting a mutation-independent shift towards cisplatin resistance in bladder cancer.

A chemokine regulatory loop induces cholesterol synthesis in lung-colonizing triple-negative breast cancer cells to fuel metastatic growth

Triple-negative breast cancer (TNBC) has a high propensity for organ-specific metastasis. However, the underlying mechanisms are not well understood. Here we show that the primary TNBC tumor-derived C-X-C motif chemokines 1/2/8 (CXCL1/2/8) stimulate lung-resident fibroblasts to produce the C-C motif chemokines 2/7 (CCL2/7), which, in turn, activate cholesterol synthesis in lung-colonizing TNBC cells and induce angiogenesis at lung metastatic sites. Inhibiting cholesterol synthesis in lung-colonizing breast tumor cells by pulmonary administration of simvastatin-carrying HER3-targeting nanoparticles reduces angiogenesis and growth of lung metastases in a syngeneic TNBC mouse model. Our findings reveal a novel, chemokine-regulated mechanism for the cholesterol synthesis pathway and a critical role of metastatic site-specific cholesterol synthesis in the pulmonary tropism of TNBC metastasis. The study has implications for the unresolved epidemiological observation that use of cholesterol-lowering drugs has no effect on breast cancer incidence but can unexpectedly reduce breast cancer mortality, suggesting interventions of cholesterol synthesis in lung metastases as an effective treatment to improve survival in individuals with TNBC.

The role of FOXC1/FOXCUT/DANCR axis in triple negative breast cancer: a bioinformatics and experimental approach

BACKGROUND

Triple-negative breast cancer (TNBC) is the most challenging subtype of breast cancer and does not benefit from the existing targeted therapies. In the present study, we used bioinformatics and experimental approaches to assess the genes that are somehow involved in the epithelial-mesenchymal transition (EMT) pathway which may explain the invasive features of TNBC.

METHOD AND RESULTS

We analyzed five GEO datasets consisting of 657 breast tumors by GEO2R online software to achieve common differentially expressed genes (DEGs) between TNBC and non-TNBC tumors. The expression of the selected coding and non-coding genes was validated in 100 breast tumors, including fifty TNBC and fifty non-TNBC samples, using quantitative Real-Time PCR (qRT-PCR). The bioinformatics approach resulted in a final DEG list consisting of ten upregulated and seventeen downregulated genes (logFC ≥|1| and P < 0.05). Co-expression network construction indicated the FOXC1 transcription factor as a central hub node. Considering the notable role of FOXC1 in EMT, the expression levels of FOXC1-related lncRNAs, lnc-FOXCUT and lnc-DANCR, were also evaluated in the studied tumors. The results of qRT-PCR confirmed notable upregulation of FOXC1, lnc-FOXCUT, and lnc-DANCR in TNBC tissues compared to non-TNBC samples (P < 0.0001, P = 0.0005, and P = 0.0008, respectively). Moreover, ROC curve analysis revealed the potential biomarker role of FOXC1 in TNBC samples.

CONCLUSION

Present study suggested that the deregulation of FOXC1/lnc-FOXCUT/lnc-DANCR axis may contribute to the aggressive features of triple-negative breast tumors. Therefore, this axis may be considered as a new probable therapeutic target in the treatment of TNBC.

Forkhead-box C1 attenuates high glucose-induced trophoblast cell injury during gestational diabetes mellitus via activating adenosine monophosphate-activated protein kinase through regulating fibroblast growth factor 19

Gestational diabetes mellitus (GDM) is a complication developed during pregnancy and recover after childbirth. The purpose of this study was to investigate the protective role of FOXC1 during GDM and the underlying mechanism. FOXC1 was downregulated in GDM placental tissues and HG-treated HTR-8/SVneo cells. Overexpression of FOXC1 prevented HG-induced inhibition of cell proliferation, migration and invasion. FOXC1 suppressed HG-induced cell apoptosis in HTR-8/SVneo cells. The apoptosis-related proteins: cleaved caspase-3, cleaved caspase-9 and BAX, were also downregulated by FOXC1 overexpression. FOXC1 increased glucose uptake and improved insulin sensitivity. The expression of FOXC1 was positively correlated with FGF19 expression. FOXC1 regulated the expression of FGF19 and phosphorylation of AMPK. Inhibition of FGF19 attenuated the biological functions of FOXC1 through inactivation of AMPK. In conclusion, this study demonstrates that FOXC1 attenuates HG-induced trophoblast cell injury through upregulating FGF19 to activate the AMPK signaling pathway during GDM, suggesting that FOXC1 is a potential therapeutic target for drug discovery in the future.

TET3- and OGT-Dependent Expression of Genes Involved in Epithelial-Mesenchymal Transition in Endometrial Cancer

TET3 is a member of the TET (ten-eleven translocation) proteins family that catalyzes the conversion of the 5-methylcytosine into 5-hydroxymethylcytosine. TET proteins can also affect chromatin modifications and gene expression independently of their enzymatic activity via interactions with other proteins. O-GlcNAc transferase (OGT), the enzyme responsible for modification of proteins via binding of N-acetylglucosamine residues, is one of the proteins whose action may be dependent on TET3. Here, we demonstrated that in endometrial cancer cells both TET3 and OGT affected the expression of genes involved in epithelial to mesenchymal transition (EMT), i.e., FOXC1, TWIST1, and ZEB1. OGT overexpression was caused by an increase in TWIST1 and ZEB1 levels in HEC-1A and Ishikawa cells, which was associated with increased O-GlcNAcylation of histone H2B and trimethylation of H3K4. The TET3 had the opposite effect on gene expressions and histone modifications. OGT and TET3 differently affected FOXC1 expression and the migratory potential of HEC-1A and Ishikawa cells. Analysis of gene expressions in cancer tissue samples from endometrial cancer patients confirmed the association between OGT or TET3 and EMT genes. Our results contribute to the knowledge of the role of the TET3/OGT relationship in the complex mechanism supporting endometrial cancer progression.

A novel variant in FOXC1 associated with atypical Axenfeld-Rieger syndrome

Mutations in the Forkhead Box C1 (FOXC1) are known to cause autosomal dominant hereditary Axenfeld-Rieger syndrome, which is a genetic disorder characterized by ocular and systemic features including glaucoma, variable dental defects, craniofacial dysmorphism and hearing loss. Due to late-onset of ocular disorders and lack of typical presentation, clinical diagnosis presents a huge challenge. In this study, we described a pathogenic in-frame variant in FOXC1 in one 5-year-old boy who is presented with hypertelorism, pupil deformation in both eyes, conductive hearing loss, and dental defects. By whole exome sequencing, we identified a 3 bp deletion in FOXC1, c.516_518delGCG (p.Arg173del) as the disease-causing variant, which was de novo and not detected in the parents, and could be classified as a "pathogenic variant" according to the American College of Medical Genetics and Genomics guidelines. After confirmation of this FOXC1 variant, clinical data on Axenfeld-Rieger syndrome-associated clinical features were collected and analyzed. Furthermore, Although the affected individual present hearing loss, however, the hearing loss is conductive and is reversible during the follow-up, which might not linke to the FOXC1 variant and is coincidental. Routine examination of FOXC1 is necessary for the genetic diagnosis of hypertelorism-associated syndrome. These findings may assist clinicians in reaching correct clinical and molecular diagnoses, and providing appropriate genetic counseling.

Enhancer recruitment of a RUNX1, HDAC1 and TLE3 co-repressor complex by mis-expressed FOXC1 blocks differentiation in acute myeloid leukemia

Tissue-inappropriate expression of FOXC1 (Forkhead Box C1) in acute myeloid leukemia confers a monocyte/macrophage lineage differentiation block. We discovered that FOXC1 interacts with RUNX1 (Runt-Related Transcription Factor 1) to stabilize a RUNX1, HDAC1 (Histone Deacetylase 1) and TLE3 (Transducin-like enhancer protein 3) repressor complex at enhancers controlling myeloid differentiation genes.

Identification and functional study of FOXC1 variants in Chinese families with glaucoma

This study aimed to identify the disease-causing gene of three Chinese families with glaucoma. Whole exome sequencing was performed on the probands and detected three different variants (c.405C>A (p.Cys135Ter), c.851G>T (p.Ser284Ile), and c.392C>T (p.Ser131Leu)) in FOXC1 as a causative gene of glaucoma, and Sanger sequencing was performed for verification and cosegregation analysis. Three in silico tools all predicted these two missense variants to be probably disease-causing. Western blot analysis, immunofluorescence, and dual-luciferase assay were further used to evaluate the effect of FOXC1 missense variants, and demonstrated that the two variants resulted in decreased transactivation activity of FOXC1 although the variants had no effect on the protein amount and the nucleus subcellar localization of FOXC1 compared with the wild type, which implies that both of two variants may be probably pathogenic. In this study, we reported two novel FOXC1 variants as well as a reported variant and the phenotypes associated to these variants, which expands the spectrum and relevant phenotypes of FOXC1 variants. Additionally, the functional analysis of FOXC1 variants provides further insight into the possible pathogenesis of anterior segment anomaly related to FOXC1.

A novel missense mutation of FOXC1 in an Axenfeld-Rieger syndrome patient with a congenital atrial septal defect and sublingual cyst: a case report and literature review

Background

Axenfeld–Rieger syndrome (ARS) is a rare autosomal dominant hereditary disease characterized primarily by maldevelopment of the anterior segment of both eyes, accompanied by developmental glaucoma, and other congenital anomalies. FOXC1 and PITX2 genes play important roles in the development of ARS.

Case presentation

The present report describes a 7-year-old boy with iris dysplasia, displaced pupils, and congenital glaucoma in both eyes. The patient presented with a congenital atrial septal defect and sublingual cyst. The patient’s family has no clinical manifestations. Next generation sequencing identified a pathogenic heterozygous missense variant in FOXC1 gene (NM_001453:c. 246C>A, p. S82R) in the patient. Sanger sequencing confirmed this result, and this mutation was not detected in the other three family members.

Conclusion

To the best of our knowledge, the results of our study reveal a novel mutation in the FOXC1 gene associated with ARS.

Down-regulated expression of miR-582 predicts poor prognosis and facilitates melanoma progression by targeting FOXC1

Melanoma is one of the most common malignant tumors that originate from nerve sheath melanocytes and are produced in the skin and other organs. This paper mainly studied the role of miR-582 in melanoma. The expression of miR-582 in melanoma cell lines and tissues was evaluated by real-time quantitative PCR. Kaplan-Meier curve and Cox proportional hazards model analysis were used to investigate the prognostic value of miR-582 in melanoma. Cell proliferation, invasion, and migration were analyzed using CCK-8 and transwell assays. The results showed that miR-582 was significantly decreased in melanoma cells and tissues. Downregulation of miR-582 was associated with ulceration, lymph node metastasis, TNM stage, and poor overall survival. The functional results showed that low expression of miR-582 can promote cell proliferation, migration, and invasion. FOXC1 was a direct target of miR-582. Overall, the expression of miR-582 is downregulated in melanoma tissues and cell lines. Low expression of miR-582 is associated with prognosis and progression of melanoma by targeting FOXC1. miR-582 may be a prognostic biomarker and a new therapeutic strategy for melanoma.

Enhancer recruitment of transcription repressors RUNX1 and TLE3 by mis-expressed FOXC1 blocks differentiation in acute myeloid leukemia

Despite absent expression in normal hematopoiesis, the Forkhead factor FOXC1, a critical mesenchymal differentiation regulator, is highly expressed in ∼30% of HOXAhigh acute myeloid leukemia (AML) cases to confer blocked monocyte/macrophage differentiation. Through integrated proteomics and bioinformatics, we find that FOXC1 and RUNX1 interact through Forkhead and Runt domains, respectively, and co-occupy primed and active enhancers distributed close to differentiation genes. FOXC1 stabilizes association of RUNX1, HDAC1, and Groucho repressor TLE3 to limit enhancer activity: FOXC1 knockdown induces loss of repressor proteins, gain of CEBPA binding, enhancer acetylation, and upregulation of nearby genes, including KLF2. Furthermore, it triggers genome-wide redistribution of RUNX1, TLE3, and HDAC1 from enhancers to promoters, leading to repression of self-renewal genes, including MYC and MYB. Our studies highlight RUNX1 and CEBPA transcription factor swapping as a feature of leukemia cell differentiation and reveal that FOXC1 prevents this by stabilizing enhancer binding of a RUNX1/HDAC1/TLE3 transcription repressor complex to oncogenic effect.

[<i<FOXC1-Mediated Effects of miR-204-5p on Melanoma Cell Proliferation]

MicroRNAs epigenetically regulate physiological and pathological processes. Previously, we found that miR-204-5p is expressed at low levels in melanoma cells, and an increase in its level leads to a change in proliferation, migration, and invasion of these cancer cells. Now, using bioinformatics analysis, it has been shown that the target of miR-204-5p is FOXC1 transcription factor, which is implicated in carcinogenesis. Using the luciferase reporter assay, it was found that miR-204-5p suppresses expression of the FOXC1 gene by binding to its 3' non-coding region. Transfection of small interfering RNA (siRNA) targeting FOXC1 into melanoma cells caused a decrease in miR-204-5p levels, which is consistent with the generally accepted concept of feedback regulation of miRNA expression by target genes. According to the results of the MTT test and fluorescence microscopy, the proliferation level of melanoma cells under the influence of siRNA to FOXC1 decreased 72 h after transfection. Changes in the ratio of cells by cell cycle phase were analyzed using flow cytometry. Regulatory relationships between FOXC1 and miR-204-5p, and an inhibitory effect of FOXC1 knockdown on melanoma cell proliferation were revealed. Based on the results, it can be assumed that miR-204-5p regulates proliferation of melanoma cells by affecting FOXC1 expression.

[FOXC1 Knockdown Reverses Gefitinib Resistance in Non-small Cell Lung Cancer]

BACKGROUND

Lung cancer is the malignant tumor with the highest incidence and mortality in China, among which non-small cell lung cancer (NSCLC) accounts for about 80%. Epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) targeted therapy has been playing an important role in treatment of NSCLC. However, unavoidable therapeutic resistance significantly limits the clinical efficacy of EGFR-TKI. As a key member of the forkhead box protein family, FOXC1 is aberrantly expressed in NSCLC and involved in NSCLC progression. The aim of this work is to investigate the effect and potential mechanism of FOXC1 on gefitinib resistance in NSCLC.

METHODS

Western blot was performed to assess the expression of FOXC1 protein in HCC827/GR cells. Immunohistochemistry (IHC) assays were performed in human NSCLC tissues with gefitinib resistance. HCC827/GR cells were transfected with shRNA specifically targeting FOXC1 mRNA and stable cell lines were established. The effects of FOXC1 on cell viability and apoptosis were analyzed using a new methyl thiazolyl tetrazolium assay (MTS assay) and flow cytometry. Self-renewal ability was determined by mammosphere-formation analysis. Quantitative real-time PCR (qRT-PCR) and Western blot were employed to detect the expression of SOX2, Nanog, OCT4 and CD133. Flow cytometry analysis were further used to detect the level of CD133. IHC assays were used to detect the levels of SOX2 and CD133 in NSCLC tissues with genfitiinb resistance. Correlations of the expressions of FOXC1, CD133 and SOX2 with each other in lung adenocarcinoma samples were analyzed based on The Cancer Genome Atlas (TCGA) database.

RESULTS

The expression of FOXC1 is significantly increased in HCC827/GR cells compared with HCC827 cells (P<0.05). IHC results showed FOXC1 was highly expressed in NSCLC tissues with gefitinib resisitance. Knockdown of FOXC1 significantly increased the sensitivity of HCC827/GR cells to gefitinib. The cell viability was decreased and the apoptosis was promoted (P<0.05). Moreover, FOXC1 knockdown apparently inhibited the expression of SOX2 and CD133, and decreased the mammosphere-formation capacity in HCC827/GR cells. In NSCLC tissues with gefitinib resistance, the expressions of SOX2 and CD133 were significantly higher compared with gefitinib-sensitive tissues (P<0.01). Meanwhile, the expressions of FOXC1, CD133 and SOX2 with each other were positively correlated (P<0.05).

CONCLUSIONS

FOXC1 could increase gefitinib resitance in NSCLC, by which mechanism is related to the regulation of cancer stem cell properties.

MicroRNA-495/TGF-β/FOXC1 axis regulates multidrug resistance in metaplastic breast cancer cells

Triple-negative metaplastic breast carcinoma (MBC) poses a significant treatment challenge due to lack of targeted therapies and chemotherapy resistance. We isolated a novel MBC cell line, BAS, which showed a molecular and phenotypic profile different from the only other metaplastic cell model, HS578T cells. To gain insight behind chemotherapeutic resistance, we generated doxorubicin (HS-DOX, BAS-DOX) and paclitaxel (HS-TX, BAS-TX) resistant derivatives of both cell lines. Drug sensitivity assays indicated a truly multidrug resistant (MDR) phenotype. Both BAS-DOX and BAS-TX showed up-regulation of FOXC1 and its experimental down-regulation re-sensitized cells to doxorubicin and paclitaxel. Experimental modulation of FOXC1 expression in MCF-7 and MDA-MB-231 cells corroborated its role in MDR. Genome-wide expression analyses identified gene expression signatures characterized by up-regulation of TGFB2, which encodes cytokine TGF-β2, in both BAS-DOX and BAS-TX cells. Pharmacological inhibition of the TGF-β pathway with galunisertib led to down-regulation of FOXC1 and increase in drug sensitivity in both BAS-DOX and BAS-TX cells. MicroRNA (miR) expression analyses identified high endogenous miR-495-3p levels in BAS cells that were downregulated in both BAS MDR cells. Transient expression of miR-495-3p mimic in BAS-DOX and BAS-TX cells caused downregulation of TGFB2 and FOXC1 and re-sensitized cells to doxorubicin and paclitaxel, whereas miR-495-3p inhibition in BAS cells led to increase in resistance to both drugs and up-regulation of TGFB2 and FOXC1. Together, these data suggest interplay between miR-495-3p, TGF-β2 and FOXC1 regulating MDR in MBC and open the exploration of novel therapeutic strategies.

EZH2 regulates expression of FOXC1 by mediating H3K27me3 in breast cancers

Triple-negative breast cancer (TNBC) is characterized by low expression of human epidermal growth factor receptor-2 (HER2), estrogen receptor (ER), and progesterone receptor (PR), which is the most aggressive subtype with poor outcome among breast cancers. The underlying mechanisms of TNBC remain unclear and there is a lack of biomarkers. In this study we conducted an in silico assay and found that FOXC1 was highly expressed in ER^-/PR^-/HER2^- breast cancers, which was confirmed by qRT-PCR, immunohistochemistry, and Western blot analysis. FOXC1 was more highly expressed in TNBCs than the other breast cancers. Kaplan-Meier plotter revealed that expression of FOXC1 was associated with overall survival (OS) of patients with breast cancers. Expression of FOXC1 was reversely associated with level of H3K27me3, which was methylated by EZH2. In MCF-7 and T47D cells, inhibition of EZH2 by DZNeP or GSK343 concentration- and time-dependently increased expression of FOXC1. Finally, we demonstrated that the expression of FOXC1 was associated with resistance of doxorubicin treatment of breast cancer cells. In conclusion, these results suggest that FOXC1 may be a potential biomarker or drug target for TNBCs, and that downregulation of FOXC1 could have therapeutic value in treatment of TNBCs.

MicroRNA miR-106a-5p targets forkhead box transcription factor FOXC1 to suppress the cell proliferation, migration, and invasion of ectopic endometrial stromal cells via the PI3K/Akt/mTOR signaling pathway

Emerging evidence has exhibited an obvious decreased expression of miR-106a-5p in the ectopic endometrial tissue of endometriosis (EMS) patients. Thus far, the pathophysiological function of miR-106a-5p in EMS is unknown. A previous study showed an increased FOXC1 expression in the ectopic endometrial tissue of patients with EMS. Moreover, we found that there was a binding site of miR-106a-5p on the 3'UTR of FOXC1 through bioinformatics predictions. Hence, we speculated that miR-106a-5p might affect the development of EMS via targeting FOXC1. We first showed a decreased level of miR-106a-5p and an increased level of FOXC1 mRNA in ectopic endometrial tissues compared with normal tissues. Functionally, we transfected ectopic endometrial stromal cells (ESCs) with miR-106a-5p mimics or NC mimics and indicated an inhibitory role of miR-106a-5p on ESC proliferation, invasion, and migration. Mechanistically, FOXC1 was found to be a target gene of miR-106a-5p. To confirm whether miR-106a-5p exerted an inhibitory activity in ESCs via targeting FOXC1, miR-106a-5p mimic was co-transfected into ESCs with the FOXC1-plasmid or vector. We found that FOXC1 overexpression evidently reversed the results caused by a miR-106a-5p mimic in ESCs. Additionally, our results demonstrated that miR-106a-5p mimic inhibited the expression of p-Akt and p-PI3K. Collectively, these results revealed that miR-106a-5p inhibited the proliferative, migratory, and invasive ability of ESCs via directly binding to FOXC1, likely through the suppression of the PI3K and its downstream signaling pathway, which offered a potential and novel therapeutic strategy for EMS treatment.

circ-PTK2 (hsa_circ_0008305) regulates the pathogenic processes of ovarian cancer via miR-639 and FOXC1 regulatory cascade

Background

Precise quantification of microRNA is challenging since circulating mRNA and rRNA in the blood are usually degraded. Therefore, it is necessary to identify specific biomarkers for ovarian cancer. This study aimed to investigate candidate circular RNAs (circRNAs) involved in the pathogenic process of ovarian cancer after inhibition of chromodomain helicase DNA binding protein 1-like (CHD1L) and the corresponding mechanism.

Methods

CHD1L mRNA-targeted siRNA was designed and induced a decreased level of CHD1L function in SK-OV-3 and OVCAR-3 cells observed via transwell and wound healing assays and assessment of epithelial–mesenchymal transition (EMT)-related protein expression by immunofluorescence (IF) and western blotting (WB). After decreasing the level of CHD1L, RNA-seq was conducted, and the circRNA expression profiles were obtained. cirRNAs were then selected and validated by PCR together with Sanger sequencing, fluorescent in situ hybridization (FISH), and reverse transcriptase-quantitative PCR (RT-qPCR). Selected circRNA function in vitro was adjusted via interference and overexpression and assessed via transwell assay, tube formation, and EMT-related protein assay by IF and WB; tumor formation in vivo was followed via hematoxylin and eosin (HE) staining and immunohistochemistry of EMT-related proteins. Based on the competing endogenous RNA prediction of circRNA targets, candidate miRNAs were found, and their downstream mRNAs targeted by the selected miRNA were identified and validated by luciferase assay. The functions of these selected miRNA and mRNA were then further investigated through transwell and WB assay of EMT-related proteins.

Results

CHD1L was significantly upregulated in ovarian cancer tissues and patients with higher expression of CHD1L had a shorter relapse-free survival (P < 0.001) and overall survival (P < 0.001). Inhibiting the level of CHD1L significantly decreased cell migration and invasion (P < 0.05), increased the expression of epithelial markers, and decreased the expression of mesenchymal markers. Following inhibition of CHD1L expression, RNA-seq was conducted and 82 circRNAs had significantly upregulated expression, while 247 had significantly downregulated expression. The circRNAs were validated by PCR, and hsa_circ_0008305 (circ-PTK2) was selected and further validated by Sanger sequencing, FISH, and RT-qPCR. Circ-PTK2 expression was significantly higher in the ovarian cancer tissues compared with normal ovary tissues (P < 0.001). By regulating the level of circ-PTK2 with siRNA and an overexpression vector, expression of circ-PTK2 was found to be positively correlated to cell migration and invasion. Overexpression of circ-PTK2 enhanced tumor formation and was correlated to expression of EMT pathway markers. Prediction of the target of circ-PTK2 was validated with dual luciferase assay and identified miR-639 and FOXC1 as the valid target of circ-PTK2 and miR-639, respectively. The RNA level of miR-639 was negatively correlated to cell proliferation and migration, whereas the mRNA level of FOXC1 was positively correlated to those processes. miR-639 mimics reversed the function of circ-PTK2 overexpression; however, interference of FOXC1 mRNA also reversed the function of circ-PTK2.

Conclusions

circ-PTK2 is an important molecule in regulating the pathogenic processes of ovarian cancer via the miR-639 and FOXC1 regulatory cascade.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01985-x.

C/EBPα Regulates FOXC1 to Modulate Tumor Growth by Interacting with PPARγ in Hepatocellular Carcinoma

BACKGROUND

Forkhead box C1 (FOXC1) is an important cancer-associated gene in tumor. PPAR-γ and C/EBPα are both transcriptional regulators involved in tumor development.

OBJECTIVE

We aimed to clarify the function of PPAR-γ, C/EBPα in hepatocellular carcinoma (HCC) and the relationship of PPAR-γ, C/EBPα and FOXC1 in HCC.

METHODS

Western blotting, immunofluorescent staining, and immunohistochemistry were used to evaluate protein expression. qRT-PCR was used to assess mRNA expression. Co-IP was performed to detect the protein interaction. And ChIP and fluorescent reporter detection were used to determine the binding between protein and FOXC1 promoter.

RESULTS

C/EBPα could bind to FOXC1 promoter and PPAR-γ could strengthen C/EBPα's function. Expressions of C/EBPα and PPAR-γ were both negatively related to FOXC1 in human HCC tissue. Confocal displayed that C/EBPα was co-located with FOXC1 in HepG2 cells. C/EBPα could bind to FOXC1 promoter by ChIP. Luciferase activity detection exhibited that C/EBPα could inhibit FOXC1 promoter activity, especially FOXC1 promoter from -600 to -300 was the critical binding site. Only PPAR-γ could not influence luciferase activity but strengthen inhibited effect of C/EBPα. Further, the Co-IP displayed that PPAR-γ could bind to C/EBPα. When C/EBPα and PPAR-γ were both high expressed, cell proliferation, migration, invasion, and colony information were inhibited enormously. C/EBPα plasmid combined with or without PPAR-γ agonist MDG548 treatment exhibited a strong tumor inhibition and FOXC1 suppression in mice.

CONCLUSION

Our data establish C/EBPα targeting FOXC1 as a potential determinant in the HCC, which supplies a new pathway to treat HCC. However, PPAR-γ has no effect on FOXC1 expression.

FOXC1 Negatively Regulates DKK1 Expression to Promote Gastric Cancer Cell Proliferation Through Activation of Wnt Signaling Pathway

Gastric cancer (GC), characterized by uncontrolled growth, is a common malignant tumor of the digestive system. The Wnt signaling pathway plays an important role in the tumorigenesis and proliferation of GC. Many studies on this signaling pathway have focused on its intracellular regulatory mechanism, whereas little attention has been given to extracellular regulatory factors. Dickkopf-1 (Dkk1) is a secretory glycoprotein, and it can bind inhibit activation of the Wnt pathway. However, the regulation and mechanism of DKK1 in the proliferation of GC remain unclear. FOXC1 plays an important role in organ development and tumor growth, but its role in GC tumor growth remains unknown. In this study, we found that the FOXC1 is highly expressed in patients with GC and high expression of FOXC1 correlates to poor prognosis. In addition, we found that the Wnt signaling pathway in GC cells with high FOXC1 expression was strongly activated. FOXC1 negatively regulates DKK1 expression by binding to its promoter region, thereby promoting the activation of Wnt pathway. FOXC1 can also form a complex with unphosphorylated β-catenin protein in the cytoplasm and then dissociates from β-catenin in the nucleus, thereby promoting the entry of β-catenin into the nucleus and regulating expression of c-MYC, which promotes the proliferation of GC cells. Our study not only reveals the function and mechanism of FOXC1 in GC, but also provides a potential target for clinic GC treatment.

Long Non-Coding RNA LINC01929 Accelerates Progression of Oral Squamous Cell Carcinoma by Targeting the miR-137-3p/FOXC1 Axis

Recently, additional long noncoding RNAs (lncRNAs) have been identified and their possible roles were investigated in a variety of human tumors. One of these lncRNAs, LINC01929, promoted the progression of some cancers, whereas its expression and biological function in human oral squamous cell carcinoma (OSCC) remains still mostly uncertain. The LINC01929 expression in OSCC tissues or cell lines was identified via quantitative real-time polymerase chain reaction. The cell counting kit-8, transwell migration, wound-healing, and flow cytometry assays were utilized to characterize the functions of LINC01929 in OSCC cells. The interactive relationships between LINC01929 and miR-137-3p, miR-137-3p and Forkhead box C1 (FOXC1) were investigated by the dual-luciferase activity assay. Our findings demonstrated that LINC01929 was highly expressed in OSCC tissue samples and cell lines, whereas miR-137-3p expression was downregulated. LINC01929 acted as a carcinogenic lncRNA with accelerated OSCC cell proliferation, migration and invasion, and suppression of apoptosis. We further indicated that LINC01929 facilitated tumor growth in xenograft mouse models. Mechanistically, LINC01929 acted as a sponge for miR-137-3p to elevate FOXC1 expression, which is the target of miR-137-3p. In addition, downregulated miR-137-3p expression rescued the suppressive behaviors of LINC01929 knockdown on the biological behaviors of OSCC cells. Taken together, LINC01929 functioned as a tumor-promoting lncRNA via the miR-137-3p/FOXC1 axis in OSCC, suggesting novel targets for OSCC therapy.

Genetic analysis of patients with primary congenital glaucoma

PURPOSE

To determine the common gene mutation in patients with primary congenital glaucoma (PCG) in the Southeast region of Turkey via genetic analysis and to evaluate whether there were other gene mutations in these patients.

METHODS

A total of 25 patients with PCG were included in this study. We performed sequence analysis including all exons of cytochrome p450 1B1 (CYP1B1), myocilin (MYOC), forkhead box C1 (FOXC1), and paired-like homeodomain 2 (PITX2) genes of the obtained samples. Further, we analyzed the results using the Nextgen analysis program.

RESULTS

The CYP1B1 gene mutation was detected in 20 (80%) of 25 patients, and FOXC1 gene mutation was detected in one (4%) patient. The mutation site of nine (45%) of the 20 CYP1B1 genes was found in the second exon. The pathogenic variant (p.Gly61Glu) was observed in 12 (60%) patients (in the first and second exons); the mutation type of six (50%) of these patients was homozygous. The mutation site of one patient with FOXC1 gene mutation was found to be in the first exon; its pathogenic variant was p.Met400lle. The mutation type in this gene was observed to be heterozygous. Lastly, there were no mutations in the MYOC, FOXC1, and PITX2 genes in combination with the CYP1B1 gene mutation.

CONCLUSION

The most common cause of PCG in our region is the CYP1B1 gene mutation, and the most frequent pathogenic variant is c.182G > A (p.Gly61Glu). We also determined that the CYP1B1 gene mutation was alone and did not occur with other gene mutations (MYOC, FOXC1, and PITX2).

Tumor-specific overexpression of histone gene, H3C14 in gastric cancer is mediated through EGFR-FOXC1 axis

Incorporation of different H3 histone isoforms/variants have been reported to differentially regulate gene expression via alteration in chromatin organization during diverse cellular processes. However, the differential expression of highly conserved histone H3.2 genes, H3C14 and H3C13 in human cancer has not been delineated. In this study, we investigated the expression of H3.2 genes in primary human gastric, brain, breast, colon, liver, and head and neck cancer tissues and tumor cell lines. The data showed overexpression of H3.2 transcripts in tumor samples and cell lines with respect to normal counterparts. Furthermore, TCGA data of individual and TCGA PANCAN cohort also showed significant up-regulation of H3.2 genes. Further, overexpressed H3C14 gene coding for H3.2 protein was regulated by FOXC1 transcription factor and G4-cassette in gastric cancer cell lines. Elevated expression of FOXC1 protein and transcripts were also observed in human gastric cancer samples and cell lines. Further, FOXC1 protein was predominantly localized in the nuclei of neoplastic gastric cells compared to normal counterpart. In continuation, studies with EGF induction, FOXC1 knockdown, and ChIP-qPCR for the first time identified a novel axis, EGFR-FOXC1-H3C14 for regulation of H3C14 gene overexpression in gastric cancer. Therefore, the changes the epigenomic landscape due to incorporation of differential expression H3 variant contributes to change in gene expression pattern and thereby contributing to pathogenesis of cancer.

A novel SIRT6 activator ameliorates neuroinflammation and ischemic brain injury via EZH2/FOXC1 axis

Ischemic stroke is the second leading cause of death worldwide with limited medications and neuroinflammation was recognized as a critical player in the progression of stroke, but how to control the overactive neuroinflammation is still a long-standing challenge. Here, we designed a novel SIRT6 activator MDL-811 which remarkably inhibited inflammatory response in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and primary mouse microglia, which were abolished by silencing SIRT6. RNA-seq screening identified the forkhead box C1 (Foxc1) is a key gene evoked by MDL-811 stimulation and is required for the anti-inflammatory effects of MDL-811. We found MDL-811-activated SIRT6 directly interacted with enhancer of zeste homolog 2 (EZH2) and promoted deacetylation of EZH2 which could bind to the promoter of Foxc1 and upregulate its expression to modulate inflammation. Moreover, our data demonstrated that MDL-811 not only ameliorated sickness behaviors in neuroinflammatory mice induced by LPS, but also markedly reduced the brain injury in ischemic stroke mice in addition to promoting long-term functional recovery. Importantly, MDL-811 also exhibited strong anti-inflammatory effects in human monocytes isolated from ischemic stroke patients, underlying an interesting translational perspective. Taken together, MDL-811 could be an alternative therapeutic candidate for ischemic stroke and other brain disorders associated with neuroinflammation.

ELAVL1 is transcriptionally activated by FOXC1 and promotes ferroptosis in myocardial ischemia/reperfusion injury by regulating autophagy

Aims

Myocardial ischemia is the most common form of cardiovascular disease and the leading cause of morbidity and mortality. Understanding the mechanisms is very crucial for the development of effective therapy. Therefore, this study aimed to investigate the functional roles and mechanisms by which ELAVL1 regulates myocardial ischemia and reperfusion (I/R) injury.

Methods

Mouse myocardial I/R model and cultured myocardial cells exposed to hypoxia/reperfusion (H/R) were used in this study. Features of ferroptosis were evidenced by LDH activity, GPx4 activity, cellular iron, ROS, LPO, and GSH levels. The expression levels of autophagy markers (Beclin-1, p62, LC3), ELAVL1 and FOXC1 were measured by qRT-PCR, immunostaining and western blot. RIP assay, biotin-pull down, ChIP and dual luciferase activity assay were employed to examine the interactions of ELAVL1/Beclin-1 mRNA and FOXC1/ELAVL1 promoter. CCK-8 assay was used to examine viability of cells. TTC staining was performed to assess the myocardial I/R injury.

Results

Myocardial I/R surgery induced ferroptosis and up-regulated ELAVL1 level. Knockdown of ELAVL1 decreased ferroptosis and ameliorated I/R injury. Si-ELAVL1 repressed autophagy and inhibition of autophagy by inhibitor suppressed ferroptosis and I/R injury in myocardial cells. Increase of autophagy could reverse the effects of ELAVL1 knockdown on ferroptosis and I/R injury. ELAVL1 directly bound with and stabilized Beclin-1 mRNA. Furthermore, FOXC1 bound to ELAVL1 promoter region and activated its transcription upon H/R exposure.

Conclusion

FOXC1 transcriptionally activated ELAVL1 may promote ferroptosis during myocardial I/R by modulating autophagy, leading to myocardial injury. Inhibition of ELAVL1-mediated autophagic ferroptosis would be a new viewpoint in the treatment of myocardial I/R injury.

Gene-specific facial dysmorphism in Axenfeld-Rieger syndrome caused by FOXC1 and PITX2 variants

Axenfeld-Rieger syndrome is a genetic condition characterized by ocular and systemic features and is most commonly caused by variants in the FOXC1 or PITX2 genes. Facial dysmorphism is part of the syndrome but the differences between both genes have never been systematically assessed. Here, 11 facial traits commonly reported in Axenfeld-Rieger syndrome were assessed by five clinical geneticists blinded to the molecular diagnosis. Individuals were drawn from the Australian and New Zealand Registry of Advanced Glaucoma in Australia or recruited through the Genetic and Ophthalmology Unit of l'Azienda Socio-Sanitaria Territoriale Grande Ospedale Metropolitano Niguarda in Italy. Thirty-four individuals from 18 families were included. FOXC1 variants were present in 64.7% of individuals and PITX2 variants in 35.3% of individuals. A thin upper lip (55.9%) and a prominent forehead (41.2%) were common facial features shared between both genes. Hypertelorism/telecanthus (81.8% vs 25.0%, p = 0.002) and low-set ears (31.8% vs 0.0%, p = 0.036) were significantly more prevalent in individuals with FOXC1 variants compared with PITX2 variants. These findings may assist clinicians in reaching correct clinical and molecular diagnoses, and providing appropriate genetic counseling.

The Axenfeld-Rieger Syndrome Gene FOXC1 Contributes to Left-Right Patterning

Precise spatiotemporal expression of the Nodal-Lefty-Pitx2 cascade in the lateral plate mesoderm establishes the left–right axis, which provides vital cues for correct organ formation and function. Mutations of one cascade constituent PITX2 and, separately, the Forkhead transcription factor FOXC1 independently cause a multi-system disorder known as Axenfeld–Rieger syndrome (ARS). Since cardiac involvement is an established ARS phenotype and because disrupted left–right patterning can cause congenital heart defects, we investigated in zebrafish whether foxc1 contributes to organ laterality or situs. We demonstrate that CRISPR/Cas9-generated foxc1a and foxc1b mutants exhibit abnormal cardiac looping and that the prevalence of cardiac situs defects is increased in foxc1a^−/−; foxc1b^−/− homozygotes. Similarly, double homozygotes exhibit isomerism of the liver and pancreas, which are key features of abnormal gut situs. Placement of the asymmetric visceral organs relative to the midline was also perturbed by mRNA overexpression of foxc1a and foxc1b. In addition, an analysis of the left–right patterning components, identified in the lateral plate mesoderm of foxc1 mutants, reduced or abolished the expression of the NODAL antagonist lefty2. Together, these data reveal a novel contribution from foxc1 to left–right patterning, demonstrating that this role is sensitive to foxc1 gene dosage, and provide a plausible mechanism for the incidence of congenital heart defects in Axenfeld–Rieger syndrome patients.

MCM3AP-AS1 promotes cisplatin resistance in gastric cancer cells via the miR-138/FOXC1 axis

The dysregulation of long non-coding RNAs (lncRNAs) serves a pivotal role in the pathogenesis and development of multiple types of human cancer, including gastric cancer (GC). MCM3AP-antisense 1 (MCM3AP-AS1) has been reported to function as a tumor promoter in various types of cancer. However, the biological function of MCM3AP-AS1 in the resistance of GC cells to cisplatin (CDDP) remains to be elucidated. The present study aimed to elucidate the mechanisms of MCM3AP-AS1 in the resistance of GC cells to CDDP. The expression levels of MCM3AP-AS1, miR-138 and FOXC1 were measured via reverse transcription-quantitative PCR. In addition, cell viability, migration and invasion were assessed via the Cell Counting Kit-8, wound healing and transwell assays, respectively. The interaction between genes was confirmed via the dual-luciferase reporter and pull-down assays. Western blot analysis was performed to detect FOXC1 protein expression. In the present study, it was demonstrated that MCM3AP-AS1 expression was upregulated in CDDP-resistant GC cells and that MCM3AP-AS1-knockdown suppressed CDDP resistance in GC cells. Moreover, the examination of the molecular mechanism indicated that MCM3AP-AS1 upregulated FOXC1 expression by sponging microRNA (miR)-138. Additionally, it was identified that the overexpression of FOXC1 abolished MCM3AP-AS1-knockdown- or miR-138 mimic-mediated inhibitory effects on CDDP resistance in GC cells. In conclusion, the present findings suggested that MCM3AP-AS1 enhanced CDDP resistance by sponging miR-138 to upregulate FOXC1 expression, indicating that MCM3AP-AS1 may be a novel promising biomarker for the diagnosis and treatment of patients with GC.

GPX8 is transcriptionally regulated by FOXC1 and promotes the growth of gastric cancer cells through activating the Wnt signaling pathway

BACKGROUND

Glutathione Peroxidase 8 (GPX8) as a member of the glutathione peroxidase (GPx) family plays an important role in anti-oxidation. Besides, dysregulation of GPX8 has been found in gastric cancer, but its detailed molecular mechanism in gastric cancer has not been reported.

METHODS

Our study detected the expression of GPX8 in gastric cancer tissues and cell lines using immunohistochemistry (IHC), western blot and qRT-PCR, and determined the effect of GPX8 on gastric cancer cells using CCK-8, colony formation, transwell migration and invasion assays. Besides, the effect of GPX8 on the Wnt signaling pathway was determined by western blot. Furthermore, the transcription factor of GPX8 was identified by bioinformatics methods, dual luciferase reporter and chromatin immunoprecipitation (CHIP) assays. In addition, the effect of GPX8 on tumor formation was measured by IHC and western blot.

RESULTS

The over-expression of GPX8 was observed in gastric cancer tissues and cells, which facilitated the proliferation, migration and invasion of gastric cancer cells as well as the tumor growth. GPX8 knockdown effectively inhibited the growth of gastric cancer cells and tumors. Moreover, GPX8 could activate the Wnt signaling pathway to promote the cellular proliferation, migration and invasion through. Furthermore, FOXC1 was identified as a transcription factor of GPX8 and mediated GPX8 expression to affect cell development processes.

CONCLUSIONS

These findings contribute to understanding the molecular mechanism of GPX8 in gastric cancer. Additionally, GPX8 can be a potential biomarker for gastric cancer therapy.

MiR-138-5p knockdown promotes osteogenic differentiation through FOXC1 up-regulation in human bone mesenchymal stem cells

This study examined the hypothesis that the microRNA miR-138-5p reduces the osteodifferentiation of human bone mesenchymal stem cells (hBMSCs) by downregulating the expression of forkhead box C1 (FOXC1). For this, hBMSCs were separated from bone marrow and osteogenic induction medium was added to stimulate osteogenic differentiation. Flow cytometric analysis was applied to evaluate the expression of cell-surface antigens associated with hBMSCs, including CD29, CD44, CD90, CD45, and CD34. qRT-PCR assays and Western blot assays were used to measure the mRNA and protein expression of miR-138-5p, osteocalcin, runt-related transcription factor 2, bone sialoprotein, alkaline phosphatase (ALP), and FOXC1. ALP staining assays and Alizarin Red staining (ARS) assays were used to confirm osteogenic differentiation. We used a luciferase assay to test the interaction between miR-138-5p and FOXC1. We demonstrated that miR-138-5p is downregulated in osteogenic differentiated hBMSCs. Further, overexpression of miR-138-5p reduced the expression of markers for osteodifferentiation, ALP activity, and ARS activity. Furthermore, we showed that FOXC1 is a downstream target gene of miR-138-5p, and that knockdown of miR-138-5p improves the osteogenesis differentiation of hBMSCs by upregulating FOXC1. The results from this study indicate miR-138-5p as a new target for osteogenic differentiation of hBMSCs and the treatment of bone defects.