Genetic Underpinnings and Audiological Characteristics in Children With Unilateral Sensorineural Hearing Loss

OBJECTIVE

Unilateral sensorineural hearing loss (USNHL) is a condition commonly encountered in otolaryngology clinics. However, its molecular pathogenesis remains unclear. This study aimed to investigate the genetic underpinnings of childhood USNHL and analyze the associated audiological features.

STUDY DESIGN

Retrospective analysis of a prospectively recruited cohort.

SETTING

Tertiary referral center.

METHODS

We enrolled 38 children with USNHL between January 1, 2018, and December 31, 2021, and performed physical, audiological, imaging, and congenital cytomegalovirus (cCMV) examinations as well as genetic testing using next-generation sequencing (NGS) targeting 30 deafness genes. The audiological results were compared across different etiologies.

RESULTS

Causative genetic variants were identified in 8 (21.1%) patients, including 5 with GJB2 variants, 2 with PAX3 variants, and 1 with the EDNRB variant. GJB2 variants were found to be associated with mild-to-moderate USNHL in various audiogram configurations, whereas PAX3 and EDNRB variants were associated with profound USNHL in flat audiogram configurations. In addition, whole-genome sequencing and extended NGS targeting 213 deafness genes were performed in 2 multiplex families compatible with autosomal recessive inheritance; yet no definite causative variants were identified. Cochlear nerve deficiency and cCMV infection were observed in 9 and 2, respectively, patients without definite genetic diagnoses.

CONCLUSION

Genetic underpinnings can contribute to approximately 20% of childhood USNHL, and different genotypes are associated with various audiological features. These findings highlight the utility of genetic examinations in guiding the diagnosis, counseling, and treatment of USNHL in children.

Biphenotypic Sinonasal Sarcoma With High-Grade Features: A Diagnostic Challenge

Biphenotypic sinonasal sarcoma (BSNS) is a rare neoplasm of the sinonasal tract. These tumors show neural and myogenic differentiation and are characterized by PAX3 translocations. The immunophenotypic features reflect their dual differentiation. They are low-grade sarcomas that show monomorphic spindle cells in sheets, fascicles, and herringbone patterns and are positive for S100 and smooth muscle actin. These tumors are common in elderly female patients and have a locally aggressive course. High-grade presentation or transformation was not documented until recently. Total 3 BSNSs have now been documented in the literature and we report a fourth tumor with high-grade transformation 8 years after the initial presentation. We identify the morphologic and immunohistochemical features of the high-grade areas and we highlight the stark differences with the low-grade areas based on literature and our specimen. We also discuss the diagnostic challenges that may come up with such a presentation.

Biphenotypic Sinonasal Sarcoma with a Novel PAX7::PPARGC1 Fusion: Expanding the Spectrum of Gene Fusions Beyond the PAX3 Gene

Biphenotypic sinonasal sarcoma (BSNS) is a rare low-grade malignancy occurring in the sinonasal tract that is characterized by dual neural and myogenic differentiation. Rearrangements involving the PAX3 gene, usually with MAML3, are a hallmark of this tumor type and their identification are useful for diagnosis. Rarely, a MAML3 rearrangement without associated PAX3 rearrangement has been described. Other gene fusions have not been previously reported. Herein, we report a 22 year-old woman with a BSNS harboring a novel gene fusion involving the PAX7 gene (specifically PAX7::PPARGC1A), which is a paralogue of PAX3. The histologic features of the tumor were typical with two exceptions: a lack of entrapment of surface respiratory mucosa and no hemangiopericytoma-like vasculature. Immunophenotypically, the tumor was notably negative for smooth muscle actin, which is usually positive in BSNS. However, the classic S100 protein-positive, SOX10-negative staining pattern was present. In addition, the tumor was positive for desmin and MyoD1 but negative for myogenin, a pattern that is common among BSNS with variant fusions. Awareness of the possibility of PAX7 gene fusions in BSNS is important as it may aid in the diagnosis of PAX3 fusion negative tumors.

Inhibitory SMAD6 interferes with BMP dependent generation of muscle progenitor cells and perturbs proximodistal pattern of murine limb muscles

The mechanism of pattern formation during limb muscle development remains poorly understood. The canonical view holds that naïve limb muscle progenitor cells (MPCs) invade a pre-established pattern of muscle connective tissue, thereby forming individual muscles. Here we show that early murine embryonic limb MPCs highly accumulate pSMAD1/5/9, demonstrating active signaling of bone morphogenetic proteins (BMP) in these cells. Overexpression of inhibitory SMAD6 in limb MPCs abrogated BMP signaling, impaired their migration and proliferation, and accelerated myogenic lineage progression. Fewer primary myofibers developed, causing an aberrant proximodistal muscle pattern. Patterning was not disturbed when SMAD6 was overexpressed in differentiated muscle, implying that the proximodistal muscle pattern depends on BMP-mediated expansion of MPCs prior to their differentiation. We show that limb MPCs differentially express Hox genes, and Hox-expressing MPCs displayed active BMP signaling. SMAD6 overexpression caused loss of HOXA11 in early limb MPCs. In conclusion, our data show that BMP signaling controls expansion of embryonic limb MPC as a prerequisite for establishing the proximodistal muscle pattern, a process that involves expression of Hox genes.

Identification of two variants in PAX3 and FBN1 in a Chinese family with Waardenburg and Marfan syndrome via whole exome sequencing

Both Warrensburg (WS) and Marfan syndrome (MFS) can impair the vision. Here, we recruited a Chinese family consisting of two WS affected individuals (II:1 and III:3) and five MFS affected individuals( I:1, II:2, III:1, III:2, and III:5) as well as one suspected MFS individual (II:4). Using whole exome sequencing (WES) and subsequent PCR-Sanger sequencing, we identified one novel heterozygous variant NM_000438 (PAX3) c.208 T > C, (p.Cys70Arg) from individuals with WS and one previous reported variant NM_000138 (FBN1) c.2740 T > A, (p.Cys914Ser) from individuals with MFS and co-segregated with the diseases. Real-time PCR and Western blot assay showed that, compared to their wild-type, both mRNAs and proteins of  PAX3 and FBN1 mutants reduced in HKE293T cells. Together, our study identified two disease-causing variants in a same Chinese family with WS and MFS, and confirmed their damaged effects on their genes' expression. Therefore, those findings expand the mutation spectrum of PAX3 and provide a new perspective for the potential therapy.

[Alveolar rhabdomyosarcoma: novel surrogate markers associated with oncogenic translocation]

BACKGROUND

Anomalies of the FOXO1 gene in alveolar rhabdomyosarcoma are associated with a worse clinical prognosis, which determines the high value of studying the status of this gene when choosing a therapy strategy. The «gold standard» for determining FOXO1 gene rearrangements is currently the fluorescent in situ hybridization (FISH) technique.

OBJECTIVE

Study of the relationship between canonical FOXO1 translocation and immunohistochemical expression of new surrogate markers in alveolar rhabdomyosarcoma to determine their predictive value.

MATERIAL AND METHODS

139 cases of rhabdomyosarcoma were retrospectively studied. The study used tissue matrix technology (TMA). On sections obtained from TMA blocks, the FISH technique was implemented using the locus-specific probe MetaSystems XL FOXO1 Break Apart (Metasystems, Germany). Immunohistochemical studies were performed on similar sections from TMA blocks with OLIG2 (Cell Marque Antibodies, clone 211F1.1) and MUC4 (Cell Marque Antibodies, clone 8G7) antibodies.

RESULTS

The final expression analysis and statistical processing using a 2x2 contingency table and Fisher's exact test passed 111 cases (76 without FOXO1 rearrangement and 35 with rearrangement). The specificity of OLIG2 and MUC4 expression for FOXO1-rearranged alveolar rhabdomyosarcoma was 85.53% and 80.26%, respectively (p<0.01).

CONCLUSION

The present study confirms the high predictive value of the expression of surrogate markers OLIG2 and MUC4 in determining the genetic status of alveolar rhabdomyosarcoma, which makes it possible to predict with high specificity the detection of the FOXO1 gene rearrangement.

PAX3-FOXO1 coordinates enhancer architecture, eRNA transcription, and RNA polymerase pause release at select gene targets

Transcriptional control is a highly dynamic process that changes rapidly in response to various cellular and extracellular cues, making it difficult to define the mechanism of transcription factor function using slow genetic methods. We used a chemical-genetic approach to rapidly degrade a canonical transcriptional activator, PAX3-FOXO1, to define the mechanism by which it regulates gene expression programs. By coupling rapid protein degradation with the analysis of nascent transcription over short time courses and integrating CUT&RUN, ATAC-seq, and eRNA analysis with deep proteomic analysis, we defined PAX3-FOXO1 function at a small network of direct transcriptional targets. PAX3-FOXO1 degradation impaired RNA polymerase pause release and transcription elongation at most regulated gene targets. Moreover, the activity of PAX3-FOXO1 at enhancers controlling this core network was surprisingly selective, affecting single elements in super-enhancers. This combinatorial analysis indicated that PAX3-FOXO1 was continuously required to maintain chromatin accessibility and enhancer architecture at regulated enhancers.

Downregulation of the paired box gene 3 inhibits the progression of skin cutaneous melanoma by inhibiting c-MET tyrosine kinase : PAX3 downregulation inhibits melanoma progression

BACKGROUND

The PAX3 (paired box gene 3) gene is highly expressed in several cancer types. However, its underlying mechanism of action in skin cutaneous melanoma (SKCM) remains unknown.

METHODS

In this study, we used the GEPIA database and western blotting to analyze the expression of PAX3. We performed the Kaplan-Meier survival analysis to evaluate the prognostic value of PAX3 in SKCM. Next, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed to evaluate the function of PAX3-related co-expressed genes. Additionally, the function and potential mechanism of action of PAX3 in SKCM were studied through functional experiments. Western blotting was used to detect the changes in the levels of epithelial-mesenchymal transition (EMT)-related and MET (c-MET tyrosine kinase) proteins following PAX3 knockdown. Finally, we assessed the correlation between PAX3 expression and the infiltration of CD4⁺/CD8⁺ T cells using the TISIDB database.

RESULTS

We found that PAX3 was overexpressed in the SKCM tissues and that these levels were indicative of a poor prognosis of SKCM. The KEGG pathway enrichment analysis showed that PAX3-related co-expressed genes were mainly associated with the oncogenic pathways. Knocking down PAX3 significantly inhibited the proliferation, invasion, and migration of SK-MEL-28 cells. The PAX3 expression was related significantly to the immune infiltration level of CD4⁺/CD8⁺ T cells.

CONCLUSIONS

Our findings demonstrated that PAX3 knockdown could reverse the EMT of tumor cells, inhibit the growth, and progression of SKCM cells. Therefore, PAX3 may have implications as a potential therapeutic target and promising prognostic biomarker for SKCM.

Fusion of the Paired Box 3 (PAX3) and Myocardin (MYOCD) Genes in Pediatric Rhabdomyosarcoma

BACKGROUND/AIM

Fusions of the paired box 3 gene (PAX3 in 2q36) with different partners have been reported in rhabdomyosarcomas and biphenotypic sinonasal sarcomas. We herein report the myocardin (MYOCD on 17p12) gene as a novel PAX3-fusion partner in a pediatric tumor with adverse clinical outcome.

MATERIALS AND METHODS

A rhabdomyo-sarcoma found in a 10-year-old girl was studied using a range of genetic methodologies.

RESULTS

The karyotype of the tumor cells was 48,XX,add(2)(q11),+del(2)(q35),add(3)(q?25),-7, del(8)(p 21),-15, add(17)(p 11), + 20, +der(?) t(?; 15) (?;q15),+mar[8]/46,XX[2]. Fluorescence in situ hybridization detected PAX3 rearrangement whereas array comparative genomic hybridization revealed genomic imbalances affecting hundreds of genes, including MYCN, MYC, FOXO3, and the tumor suppressor gene TP53. A PAX3-MYOCD fusion transcript was found by RNA sequencing and confirmed by Sanger sequencing.

CONCLUSION

The investigated rhabdomyosarcoma carried a novel PAX3-MYOCD fusion gene and extensive additional aberrations affecting the allelic balance of many genes, among them TP53 and members of MYC and FOXO families of transcription factors.

The vascularization, innervation and myogenesis of early regenerated tail in Gekko japonicus

Many species of lizards are capable of tail regeneration. There has been increased interest in the study of lizard tail regeneration in recent years as it is an amenable regeneration model for amniotes. In this study, Gekko japonicus was used as a model to investigate the initiation of vascularization, innervation and myogenesis during tail regeneration. We found that angiogenesis and axon regeneration occurred almost simultaneously within 4 days post amputation. The results showed that the endothelial cells of the original vasculature proliferated and extended into the blastema as capillary vessels, which inter-connected to form a capillary network. The nerve fibers innervated the regenerated tissue from the original spinal cord and dorsal root ganglia, and the fiber bundles increased during 14 days. Regenerating muscle tissues emerged 2 weeks after amputation. PAX3 and PAX7 expression were detected during myogenesis, with PAX7 showing a continuous increase in expression from day 3 until the day 14, whereas PAX3 reached a peak level on day 10 day post amputation, and then declined quickly to level as normal control on day 14. PCNA and PAX3 double-positive satellite cells were observed in the original rostral tissues, indicating the involvement of satellite cell proliferation during tail regeneration. Taken together, these data suggest that tail regeneration in Gekko japonicus involved rapid angiogenesis from the beginning to the day 10 and followed by capillary remodeling. The innervation of regenerated tail was significant on day 4 and increased gradually during regeneration, while the regenerated muscle tissues was obvious on day 14 after amputation.

Biphenotypic sinonasal sarcoma: Report of 3 cases with a review of literature

Biphenotypic sinonasal sarcoma (BSNS) is a rare recently described distinct spindle cell sarcoma which arises exclusively in the sinonasal region and is characterized by concomitant neural and myogenic differentiation. Before this neoplasm was characterized, most were classified as other entities including adult fibrosarcoma, monophasic synovial sarcoma and malignant peripheral nerve sheath tumor. By immunohistochemistry, these tumors characteristically express S100 and smooth muscle actin (SMA) and/or muscle specific actin (MSA). Most cases harbor rearrangements of PAX3 (paired box gene 3), and the most frequent translocation partner is MAML3 (mastermind like transcriptional coactivator 3). Herein, we described three cases of BSNS involving the nasal cavity with or without paranasal sinus involvement. We also did a literature review of the clinical features, histologic and immunophenotypic findings, cytogenetics, pathogenesis and behavior of this rare entity.

Master regulators of skeletal muscle lineage development and pluripotent stem cells differentiation

In vertebrates, the skeletal muscles of the body and their associated stem cells originate from muscle progenitor cells, during development. The specification of the muscles of the trunk, head and limbs, relies on the activity of distinct genetic hierarchies. The major regulators of trunk and limb muscle specification are the paired-homeobox transcription factors PAX3 and PAX7. Distinct gene regulatory networks drive the formation of the different muscles of the head. Despite the redeployment of diverse upstream regulators of muscle progenitor differentiation, the commitment towards the myogenic fate requires the expression of the early myogenic regulatory factors MYF5, MRF4, MYOD and the late differentiation marker MYOG. The expression of these genes is activated by muscle progenitors throughout development, in several waves of myogenic differentiation, constituting the embryonic, fetal and postnatal phases of muscle growth. In order to achieve myogenic cell commitment while maintaining an undifferentiated pool of muscle progenitors, several signaling pathways regulate the switch between proliferation and differentiation of myoblasts. The identification of the gene regulatory networks operating during myogenesis is crucial for the development of in vitro protocols to differentiate pluripotent stem cells into myoblasts required for regenerative medicine.

Case Report: A Novel Gross Deletion in PAX3 (10.26 kb) Identified in a Chinese Family With Waardenburg Syndrome by Third-Generation Sequencing

Waardenburg syndrome (WS) is a group of autosomal-dominant hereditary conditions with a global incidence of 1/42,000. WS can be categorized into at least four types: WS1–4, and these are characterized by heterochromia iridis, white forelock, prominent nasal root, dystopia canthorum, hypertrichosis of the medial part of the eyebrows, and deaf-mutism. WS3 is extremely rare, with a unique phenotype (upper limb abnormality). Heterozygous mutations of PAX3 are commonly associated with WS1, whereas partial or total deletions of PAX3 are often observed in WS3 cases. Deletions, together with insertions, translocations, inversions, mobile elements, tandem duplications, and complexes, constitute structural variants (SVs), which can be fully and accurately detected by third-generation sequencing (TGS), a new generation of high-throughput DNA sequencing technology. In this study, after failing to identify the causative gene by Sanger sequencing, SNP-array, and whole-exome sequencing (WES), we finally detected a heterozygous gross deletion of PAX3 (10.26kb, chr2: 223153899-223164405) in a WS family by TGS. Our description would enrich the genetic map of WS and help us to further understand this disease. Our findings also demonstrated the value of TGS in clinical genetics researches.

A novel PAX3 mutation in a Chinese Han family with Waardenburg syndrome type 1

OBJECTIVES

To determine the clinical characteristics and genetic causes of Waardenburg syndrome type 1 (WS1) present in a Chinese Han family.

METHODS

Evaluations, including the familial history, clinical features and audiological tests, were performed on the proband and her parents. Genetic analyses were conducted using targeted next-generation sequencing of 144 known deafness genes, and confirmed by Sanger sequencing. Bioinformatics analyses of the candidate variant were performed.

RESULTS

The proband suffered from moderate hearing loss of the right ear, and her mother suffered from profound congenital bilateral hearing loss. The proband exhibited a left blue iris. The calculated W index of the proband was 2.61, while her mother's W index was 2.12. The proband and her mother were diagnosed with WS1 according to the Waardenburg Syndrome Consortium criteria. A novel missense variant NM_181457.3: c.127G > T; p.(Gly43Cys) in exon 2 in Paired Box 3 (PAX3) was identified in the proband and her mother, but this variant was not detected in the father and the controls. This variant was not reported in the HGMD, ClinVar, 1000G and ESP6500 databases.

CONCLUSION

We identified a novel missense variant in exon 2 of PAX3 as the genetic cause of WS1 in this two-generation family, which broadened the genetic spectrum of WS1.

[Genotype and phenotype analysis of a family with Waardenburg syndrome type Ⅰcaused by a novel mutation in PAX3 gene]

Objective:To identify gene mutation and analysis the association between clinical characterizes and the mutations in a family of Waardenburg syndrome （WS） type I in Yunnan, China. Methods:With informed consent, the proband with WS phenotype and his family members were given medical history collection, physical examination and audiological evaluation. Peripheral blood was obtained, genomic DNA was extracted, and deafness related genes were detected by high-throughput sequencing. Sanger sequencing was used to verify the mutation sites of proband and his family members. Results:C. 602C>G mutation in exon 5 of PAX3 gene was identified, which is nonsense mutation and may cause a truncated protein. The mutation cause 201 amino acid of the protein changed from serine to stop codon. According to the American College of Medical Genetics and Genomics （ACMG）, it is considered as Pathogenicity（PVS1+PM2+PP3）. This mutation has not been included in the database also not been reported in the literature. Conclusion:Combined with the results of clinical diagnosis and gene diagnosis, this mutation was considered as the cause of the disease. This study enriched mutation spectrum of PAX3 gene.

High Genetic Heterogeneity in Chinese Patients With Waardenburg Syndrome Revealed by Next-Generation Sequencing

Objective

This study aimed to explore the genetic causes of probands who were diagnosed with Waardenburg syndrome (WS) or congenital sensorineural hearing loss.

Methods

A detailed physical and audiological examinations were carried out to make an accurate diagnosis of 14 patients from seven unrelated families. We performed whole-exome sequencing in probands to detect the potential genetic causes and further validated them by Sanger sequencing in the probands and their family members.

Results

The genetic causes for all 14 patients with WS or congenital sensorineural hearing loss were identified. A total of seven heterozygous variants including c.1459C > T, c.123del, and c.959-409_1173+3402del of PAX3 gene (NM_181459.4), c.198_262del and c.529_556del of SOX10 gene (NM_006941.4), and c.731G > A and c.970dup of MITF gene (NM_000248.3) were found for the first time. Of these mutations, we had confirmed two (c.1459C > T and c.970dup) are de novo by Sanger sequencing of variants in the probands and their parents.

Conclusion

We revealed a total of seven novel mutations in PAX3, SOX10, and MITF, which underlie the pathogenesis of WS. The clinical and genetic characterization of these families with WS elucidated high heterogeneity in Chinese patients with WS. This study expands the database of PAX3, SOX10, and MITF mutations and improves our understanding of the causes of WS.

How Neural Crest Transcription Factors Contribute to Melanoma Heterogeneity, Cellular Plasticity, and Treatment Resistance

Cutaneous melanoma represents one of the deadliest types of skin cancer. The prognosis strongly depends on the disease stage, thus early detection is crucial. New therapies, including BRAF and MEK inhibitors and immunotherapies, have significantly improved the survival of patients in the last decade. However, intrinsic and acquired resistance is still a challenge. In this review, we discuss two major aspects that contribute to the aggressiveness of melanoma, namely, the embryonic origin of melanocytes and melanoma cells and cellular plasticity. First, we summarize the physiological function of epidermal melanocytes and their development from precursor cells that originate from the neural crest (NC). Next, we discuss the concepts of intratumoral heterogeneity, cellular plasticity, and phenotype switching that enable melanoma to adapt to changes in the tumor microenvironment and promote disease progression and drug resistance. Finally, we further dissect the connection of these two aspects by focusing on the transcriptional regulators MSX1, MITF, SOX10, PAX3, and FOXD3. These factors play a key role in NC initiation, NC cell migration, and melanocyte formation, and we discuss how they contribute to cellular plasticity and drug resistance in melanoma.

M-Cadherin Is a PAX3 Target During Myotome Patterning

PAX3 belongs to the paired-homeobox family of transcription factors and plays a key role as an upstream regulator of muscle progenitor cells during embryonic development. Pax3-mutant embryos display impaired somite development, yet the consequences for myotome formation have not been characterized. The early myotome is formed by PAX3-expressing myogenic cells that delaminate from the dermomyotomal lips and migrate between the dermomyotome and sclerotome where they terminally differentiate. Here we show that in Pax3-mutant embryos, myotome formation is impaired, displays a defective basal lamina and the regionalization of the structural protein Desmin is lost. In addition, this phenotype is more severe in embryos combining Pax3-null and Pax3 dominant-negative alleles. We identify the adhesion molecule M-Cadherin as a PAX3 target gene, the expression of which is modulated in the myotome according to Pax3 gain- and loss-of-function alleles analyzed. Taken together, we identify M-Cadherin as a PAX3-target linked to the formation of the myotome.

miR-299-3p suppresses cell progression and induces apoptosis by downregulating PAX3 in gastric cancer

Gastric cancer (GC) is ranked the fourth leading cause of cancer-related death, with an over 75% mortality rate worldwide. In recent years, miR-299-3p has been identified as a biomarker in multiple cancers, such as acute promyelocytic leukemia, thyroid cancer, and lung cancer. However, the regulatory mechanism of miR-299-3p in GC cell progression is still largely unclear. Cell viability and apoptosis tests were performed by CCK8 and flow cytometry assay, respectively. Transwell assay was recruited to examine cell invasion ability. The interaction between miR-299-3p and PAX3 was determined by the luciferase reporter system. PAX3 protein level was evaluated by western blot assay. The expression of miR-299-3p was downregulated in GC tissues and cell lines (MKN-45, AGS, and MGC-803) compared with the normal tissues and cells. Besides, overexpression of miR-299-3p significantly suppressed proliferation and invasion and promoted apoptosis in GC. Next, we clarified that PAX3 expression was regulated by miR-299-3p using a luciferase reporter system, qRT-PCR, and western blot assay. Additionally, downregulation of PAX3 repressed GC cell progression. The rescue experiments indicated that restoration of PAX3 inversed miR-299-3p-mediated inhibition on cell proliferation and invasion. miR-299-3p suppresses cell proliferation and invasion as well as induces apoptosis by regulating PAX3 expression in GC, representing desirable biomarkers for GC diagnosis and therapy.

Four mutations in MITF, SOX10 and PAX3 genes were identified as genetic causes of waardenburg syndrome in four unrelated Iranian patients: case report

Background

Waardenburg syndrome (WS) is a rare genetic disorder. The purpose of this study was to investigate clinical and molecular characteristics of WS in four probands from four different Iranian families.

Case presentation

The first patient was a 1-year-old symptomatic boy with congenital hearing loss and heterochromia iridis with a blue segment in his left iris. The second case was a 1.5-year-old symptomatic girl who manifested congenital profound hearing loss, brilliant blue eyes, and skin hypopigmentation on the abdominal region at birth time. The third patient was an 8-month-old symptomatic boy with developmental delay, mild atrophy, hypotonia, brilliant blue eyes, skin hypopigmentation on her hand and foot, Hirschsprung disease, and congenital profound hearing loss; the fourth patient was a 4-year-old symptomatic boy who showed dystopia canthorum, broad nasal root, synophrys, skin hypopigmentation on her hand and abdomen, brilliant blue eyes, and congenital profound hearing loss. Whole exome sequencing (WES) was used for each proband to identify the underlying genetic factor. Sanger sequencing was performed for validation of the identified mutations in probands and the available family members. A novel heterozygous frameshift mutation, c.996delT (p.K334Sfs*15), on exon 8 of the MITF gene was identified in the patient of the first family diagnosed with WS2A. Two novel de novo heterozygous mutations including a missense mutation, c.950G > A (p.R317K), on exon 8 of the MITF gene, and a frameshift mutation, c.684delC (p.E229Sfs*57), on the exon 3 of the SOX10 gene were detected in patients of the second and third families with WS2A and PCWH (Peripheral demyelinating neuropathy, Central dysmyelinating leukodystrophy, Waardenburg syndrome, Hirschsprung disease), respectively. A previously reported heterozygous frameshift mutation, c.1024_1040del AGCACGATTCCTTCCAA, (p.S342Pfs*62), on exon 7 of the PAX3 gene was identified in the patient of the fourth family with WS1.

Conclusions

An exact description of the mutations responsible for WS provides useful information to explain the molecular cause of clinical features of WS and contributes to better genetic counseling of WS patients and their families.

Circular RNA circANKIB1 promotes the progression of osteosarcoma by regulating miR-217/PAX3 axis

Background

Circular RNAs (circRNAs) have been discovered to exert essential roles in human cancers, including osteosarcoma (OS). The aim of this study was to investigate the exact roles and regulatory mechanism of circRNA ankyrin repeat and IBR domain containing 1 (circANKIB1) in OS.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the expression levels of circANKIB1, microRNA-217 (miR-217) and paired box 3 (PAX3). Cell proliferation was assessed by colony formation assay. Cell cycle distribution and apoptosis rate were determined by flow cytometry analysis. Wound healing assay and transwell assay were employed to evaluate cell migration and invasion abilities. Western blot assay was used to analyze the protein levels of PAX3, E-cadherin and Vimentin. Targeting relationship between miR-217 and circANKIB1 or PAX3 was predicted by Circular RNA Interactome or TargetScan and demonstrated by dual-luciferase reporter assay. The mice xenograft model was established to confirm the role of circANKIB1 in vivo.

Results

CircANKIB1 and PAX3 were high-expressed, whereas miR-217 was low-expressed in OS tissues and cells. Knockdown of circANKIB1 inhibited the progression of OS by reducing cell proliferation, migration, invasion, and tumor growth (in vivo), and inducing apoptosis. MiR-217 was a direct target of circANKIB1, and its inhibition reversed the inhibitory effect of circANKIB1 knockdown on the progression of OS cells. Moreover, PAX3 was a direct target of miR-217, and miR-217 exerted the anti-tumor role in OS cells by targeting PAX3. Furthermore, circANKIB1 positively regulated PAX3 expression by sponging miR-217.

Conclusion

Knockdown of circANKIB1 suppressed OS progression by upregulating miR-217 and downregulating PAX3, which might provide a novel insight into the pathogenesis of OS.

Survival outcomes of patients with localized FOXO1 fusion-positive rhabdomyosarcoma treated on recent clinical trials: A report from the Soft Tissue Sarcoma Committee of the Children's Oncology Group

BACKGROUND

The objective of this analysis was to evaluate the clinical factors influencing survival outcomes in patients with localized (clinical group I-III), FOXO1 fusion-positive rhabdomyosarcoma (RMS).

METHODS

Patients with confirmed FOXO1 fusion-positive RMS who were enrolled on 3 completed clinical trials for localized RMS were included in the analytic cohort. Outcomes were analyzed using the Kaplan-Meier method to estimate event-free survival (EFS) and overall survival (OS), and the curves were compared using the log-rank test. A Cox proportional hazards regression model was used to perform multivariate analysis of prognostic factors that were significant in the univariate analysis.

RESULTS

The estimated 4-year EFS and OS of 269 patients with localized, FOXO1 fusion-positive RMS was 53% (95% CI, 47%-59%) and 69% (95% CI, 63%-74%), respectively. Univariate analysis revealed that several known favorable clinical characteristics, including age at diagnosis between 1 and 9 years, complete surgical resection, tumor size ≤5 cm, favorable tumor site, absence of lymph node involvement, confinement to the anatomic site of origin, and PAX7-FOXO1 fusion, were associated with improved outcomes. Multivariate analysis identified older age (≥10 years) and large tumor size (>5 cm) as independent, adverse prognostic factors for EFS within this population, and patients who had both adverse features experienced substantially inferior outcomes.

CONCLUSIONS

Patients with localized, FOXO1 fusion-positive RMS can be further risk stratified based on clinical features at diagnosis, and older patients with large primary tumors have the poorest prognosis.

Phenotypic diversity and genetic complexity of PAX3-related Waardenburg syndrome

Waardenburg syndrome subtypes 1 and 3 are caused by pathogenic variants in PAX3. We investigated 12 individuals from four unrelated families clinically diagnosed with Waardenburg syndrome type 1/3. Novel pathogenic variants identified in PAX3 included single nucleotide variants (c.166C>T, c.829C>T), a 2-base pair deletion (c.366_367delAA) and a multi-exonic deletion. Two novel variants, c.166C>T and c.829C>T and a previously reported variant, c.256A>T in PAX3 were evaluated for their nuclear localization and ability to activate MITF promoter. The coexistence of two subtypes of Waardenburg syndrome with pathogenic variants in PAX3 and EDNRB was seen in one of the affected individuals. Multiple genetic diagnoses of Waardenburg syndrome type 3 and autosomal recessive deafness 1A was identified in an individual. We also review the phenotypic and genomic spectrum of individuals with PAX3-related Waardenburg syndrome reported in the literature.

Identification and functional analysis of a novel missense mutation of PAX3 associated with Waardenburg syndrome type I

PURPOSE

Waardenburg syndrome type 1 (WS1) is a rare genetic disorder characterized by dystopia canthorum, abnormal iris pigmentation, and congenital hearing loss with variable penetrance.WS1 is caused by mutations in paired box gene 3 (PAX3). The current study aimed to investigate the genetic cause of hearing loss in a four-generation Chinese WS1 family.

METHODS

The phenotype of the study family was characterized using clinical evaluation and pedigree analysis. Target region high-throughput sequencing system was designed to screen the all coding exons and flanking intronic sequences of the six WS-associated genes. Sanger sequencing was used to identify the causative nucleotide changes and perform the co-segregating analysis. The expression, subcellular distribution, and transcriptional activity of the mutant PAX3 protein were analysis to reveal the functional consequences of the mutation.

RESULTS

Based on diagnostic criteria, the proband of this pedigree classified as WS1. We identified a novel missense mutation (c.117 C > A, p. Asn39Lys) in exon 2 of the PAX3 gene. In vitro, the Asn39Lys PAX3 retained nuclear distribution ability. However, it failed to activate the melanocyte inducing transcription factor (MITF) promoter and impaired the function of WT PAX3.

CONCLUSIONS

Our study reports a novel missense PAX3 mutation in a Chinese family and shows haploinsufficiency may be the underlying mechanism for the WS1 phenotype.

A Novel PAX3 Mutation in a Chinese Family with Waardenburg Syndrome Type 1

Aims: To determine the clinical characteristics and genetic cause of Waardenburg syndrome type 1 (WS1) in a Chinese family. Materials and Methods: Evaluations, including history, clinical features, and audiological tests, were performed on the proband and her parents. Genetic analyses were performed targeting 144 known deafness genes using a next-generation sequencing panel. Bioinformatic analyses were used to analyze the candidate mutation. Results: The proband and her parents suffered from congenital bilateral profound hearing loss. Her mother exhibited bilateral blue irides. WS1 was diagnosed in the proband and her mother according to the Waardenburg syndrome consortium criteria: the calculated W index of the proband was 2.39 and that of her mother was 2.31. A novel mutation c.1076_1077del (p.Thr359fs) in exon 7 of the PAX3 gene (paired box 3) was identified in the proband and her mother that was absent in the father and controls. Conclusion: Mutations in exon 7 of the PAX3 gene are rare. We identified a novel frameshift mutation in exon 7 of the PAX3 gene that we determined was responsible for WS1 in this family.

Two novel mutations of PAX3 and SOX10 were characterized as genetic causes of Waardenburg Syndrome

Background

The objective of this study was to investigate the genetic causes of two probands diagnosed as Waardenburg syndrome (WS type I and IV) from two unrelated Chinese families.

Methods

PAX3 and SOX10 were the main pathogenic genes for WS type I (WS I) and IV (WS IV), respectively; all coding exons of these genes were sequenced on the two probands and their family members. Luciferase reporter assay and co‐immunoprecipitation (CO‐IP) were conducted to verify potential functional outcomes of the novel mutations.

Results

The first proband is a 9 years old girl diagnosed with WS I. A novel PAX3 heterozygous mutation of c.372‐373delGA (p.N125fs) was identified, which results in a frameshift and truncation of PAX3 protein. In family II, a 2 years old girl was diagnosed with WS IV, and Sanger sequencing revealed a de novo SOX10 mutation of c.1114insTGGGGCCCCCACACTACACCGAC (p.Q372fs), a frameshift mutation that extends the amino acid chain of SOX10 protein. Functional studies indicated that the novel mutation of SOX10 had no effects on the interaction of SOX10 and PAX3, but reduced transactivate capacity of melanocyte inducing transcription factor (MITF) promoter. Both PAX3 and SOX10 mutation‐induced defects of MITF transcription might contribute to the WS pathogenesis.

Conclusion

We revealed a novel mutation in PAX3 and a de novo mutation in SOX10, which might account for the underlying pathogenesis of WS. This study expands the database of both PAX10 and PAX3 mutations and improves our understanding of the causes of WS.

The clinical and genetic research of Waardenburg syndrome type I and II in Chinese families

OBJECTIVE

Waardenburg Syndrome (WS) is a neurocristopathy with an autosomal dominant mode of inheritance and highly genetic heterogeneity. To date, mutations of PAX3, SOX10, MITF, EDNRB, EDN3 and SNAI2 have been implicated in the pathogenesis of WS. In this study, we aimed to identify pathogenic genes among WS families and to analyze the pathogenic relationship between genotypes and phenotypes.

METHODS

In this study, all six families studied were from Hubei province, China.WS patients underwent screening for all deafness genes including PAX3, SOX10, MITF, EDNRB, EDN3 and SNAI2 using Massively Parallel Sequencing (MPS) and validation of mutations using Sanger sequencing.

RESULTS

Clinical evaluation revealed prominent phenotypic variability in Hubei WS patients. Two WS1 families and four WS2 families were diagnosed in six families. Sensorineural hearing loss was the most common, followed by iris pigmentary abnormality. Molecular genetic analysis of the WS genes for six families revealed five novel heterozygous mutations. Two mutations occurred in the PAX3 gene: one nonsense mutation c.667C > T(p.Arg223Ter) and one missense mutation c.220C > T(p.Arg74Cys).One missense mutation c.331T > C (p.Phe111Leu) and one nonsense mutation c.346C > T(p.Gln116Ter) were detected in the SOX10 gene. Two mutations were detected in the MITF gene: one splice site mutation c.859-1G > A and one nonsense mutation c.859G > T(p.Glu287Ter). Among them, the mutations (SOX10 c.331T > C and MITF c.859G > T) were de novo mutations.

CONCLUSION

In this study, six mutations were found to be associated with the phenotype of patients. Our data helped illuminate the phenotypic and genotypic spectrum of WS in Hubei province and could have implications for the genetic counseling of WS in Hubei province.

Soft Tissue Special Issue: Biphenotypic Sinonasal Sarcoma: A Review with Emphasis on Differential Diagnosis

Biphenotypic sinonasal sarcoma is an anatomically restricted low-grade malignant neoplasm with dual neural and myogenic differentiation composed of a monotonous population of spindled cells with herringbone/fascicular architecture. These tumors demonstrate a unique immunoprofile with relatively consistent S100-protein and actin expression in conjunction with more variable desmin, myogenin and myoD1 staining. SOX10 is uniformly negative. Genetically, the majority of tumors harbor PAX3-MAML3 fusions, with alternate PAX3 partners including FOXO1, NCOA1, NCOA2 and WWTR1. Although the differential diagnosis of BSNS is broad, careful morphologic inspection together with targeted ancillary studies is often sufficient to arrive at the correct diagnosis. As these tumors have significant local recurrence rates but lack metastatic potential, awareness and accurate diagnosis of this rare and newly described neoplasm is critical for appropriate management.

Prognostic implications of forkhead box protein O1 (FOXO1) and paired box 3 (PAX3) in epithelial ovarian cancer

BACKGROUND

Transcription factors forkhead box protein O1 (FOXO1) and paired box 3 (PAX3) have been reported to play important roles in various cancers. However, their role in epithelial ovarian cancer (EOC) has not been elucidated yet. Therefore, we evaluated the expression and clinical significance of FOXO1 and PAX3 in EOC.

METHODS

Immunohistochemical analyses of FOXO1 and PAX3 in 212 EOCs, 57 borderline ovarian tumors, 153 benign epithelial ovarian tumors, and 79 nonadjacent normal epithelial tissues were performed using tissue microarray. Various clinicopathological variables, including the survival of EOC patients, were compared. In addition, the effect of FOXO1 on cell growth was assessed in EOC cell lines.

RESULTS

FOXO1 and PAX3 protein expression levels were significantly higher in EOC tissues than in nonadjacent normal epithelial tissues, benign tissues, and borderline tumors (all p < 0.001). In EOC tissues, FOXO1 expression was positively correlated with PAX3 expression (Spearman's rho = 0.118, p = 0.149). Multivariate survival analysis revealed that high FOXO1 expression (hazard ratio = 2.77 [95% CI, 1.48-5.18], p = 0.001) could be an independent prognostic factor for overall survival. Most importantly, high expression of both FOXO1 and PAX3 showed a high hazard ratio (4.60 [95% CI, 2.00-10.55], p < 0.001) for overall survival. Also in vitro results demonstrated that knockdown of FOXO1 was associated with decreased cell viability, migration, and colony formation.

CONCLUSIONS

This study revealed that high expression of FOXO1/PAX3 is an indicator of poor prognosis in EOC. Our results suggest the promising potential of FOXO1 and PAX3 as prognostic and therapeutic markers. The possible link between biological functions of FOXO1 and PAX3 in EOC warrants further studies.

Forkhead box protein O1 (FOXO1) and paired box gene 3 (PAX3) overexpression is associated with poor prognosis in patients with cervical cancer

PURPOSE

Forkhead box protein O1 (FOXO1) and paired box gene 3 (PAX3) have been reported to play an imported role in human cancers, but their role in cervical cancer has not yet been clarified. In this study, we evaluated the functional role of FOXO1 in cervical cancer cells and investigated the expression and clinical significance of FOXO1 and PAX3 in cervical lesions.

METHODS

In vitro assessment of cell function by cell viability, migration, and invasion assays were performed on FOXO1-knockdown cervical cancer cells. Immunohistochemical (IHC) staining analyses of FOXO1 and PAX3 were performed with a tissue microarray (TMA). The clinical significance was evaluated by comparing the data with various clinicopathologic characteristics, including survival of patients with cervical cancer.

RESULTS

In vitro results revealed that knockdown of FOXO1 is associated with decreased cell viability (p < 0.001), migration (p < 0.001), and invasion (p < 0.05), supporting the oncogenic role of FOXO1 in cervical cancer. FOXO1 and PAX3 expression was significantly higher in CIN (both p < 0.001) and cancer tissue (both p < 0.001) than in normal tissue. Multivariate analysis indicated that FOXO1 expression (hazard ratio 4.01 [95% CI 1.22-13.10], p = 0.021) and an advanced FIGO stage (hazard ratio 3.89 [95% CI 1.35-11.19], p = 0.012) were independent prognostic factors for overall survival.

CONCLUSIONS

This study reveals increased FOXO1 and PAX3 expression in cervical cancers and indicates an oncogenic role of FOXO1 in cervical cancer cells that correlates with poor patient survival.

OLIG2 is a marker of the fusion protein-driven neurodevelopmental transcriptional signature in alveolar rhabdomyosarcoma

Alveolar rhabdomyosarcoma (RMS) is associated with an underlying pathogenic translocation involving either PAX3 or PAX7 and FOXO1. The presence or absence of this fusion defines the biology and clinical behavior of this subtype of RMS and its identification in tumors is relevant to prognostication and treatment planning. To further explore the unique characteristics of fusion-driven RMS, we leveraged a published gene expression data set to perform an unbiased comparison of 33 fusion-positive and 25 fusion-negative RMS cases. Our analyses revealed 1790 expressed loci with more than two-fold differential expression at a threshold of P < .05. Genes with increased expression in fusion-positive relative to fusion-negative RMS were significantly enriched for those involved in "nervous system development," "neuron differentiation," and "neurogenesis," highlighting a neurodevelopmental gene expression signature driven by the alveolar RMS-associated fusion protein. We show that neurodevelopmental genes are enriched near PAX3-FOXO1 fusion protein binding sites, suggesting a genome-wide fusion protein-mediated activation of cis regulatory elements. Among the genes with differential expression in fusion-positive versus fusion-negative RMS, we identified expression of the transcriptional regulator of motor neuron and oligodendrocyte development, OLIG2, as a marker of the fusion protein-dependent neurodevelopmental signature. Immunohistochemical analysis of a cohort of 73 RMS specimens revealed OLIG2 expression in 96.4% of fusion-positive RMS (N = 27/28), but only in 6.7% of fusion-negative RMS (N = 3/45; P < .001). The proportion of OLIG2-expressing cells in fusion-negative cases did not exceed 5%, while 92.9% of fusion-positive cases showed expression in at least 5% of cells. Our findings identify OLIG2 expression as a unique manifestation of a neurodevelopmental gene expression signature driven by the oncogenic fusion protein characteristic of alveolar RMS, which may aid in the diagnostic and prognostic distinction of fusion-positive cases.

Bmi1 Suppresses Adipogenesis in the Hematopoietic Stem Cell Niche

Bone marrow stromal cells (BMSCs) that express high levels of stem cell factor (SCF) and CXC chemokine ligand 12 (CXCL12) are one crucial component of the hematopoietic stem cell (HSC) niche. While the secreted factors produced by BMSCs to support HSCs have been well described, little is known regarding the transcriptional regulators controlling the cell fate of BMSCs and thus indirectly maintaining HSCs. BMI1 is a polycomb group protein that regulates HSCs both cell intrinsically and extrinsically, but it is unknown in which cell type and how BMI1 functions to maintain HSCs extrinsically. Here we show that Bmi1 maintains HSCs by preventing adipogenic differentiation of BMSCs. Bmi1 is highly expressed in BMSCs but becomes downregulated upon adipogenic differentiation and during aging. Deleting Bmi1 from BMSCs increased marrow adipocytes, induced HSC quiescence and depletion, and impaired hematopoiesis. We found that BMI1 repressed multiple developmental programs in BMSCs by safeguarding the repressive epigenetic marks histone H2A ubiquitylation and H3 lysine 27 trimethylation. We identified a novel adipogenic program governed by Pax3, which BMI1 repressed in BMSCs. Our results establish Bmi1 as a critical regulator of BMSC cell fate that suppresses marrow adipogenesis to create a supportive niche for HSCs.

A novel mutation of the PAX3 gene in a Chinese family with Waardenburg syndrome type I

BACKGROUND

To analyze the clinical phenotypes and genetic variants of a Chinese family with Waardenburg syndrome (WS) and to explore the possible molecular pathogenesis of WS.

METHODS

The clinical data from a patient and his family were collected. The genomic DNA of the patient and his family was purified from their peripheral blood. All exons and flanking sequences of the MITF, PAX3, SOX10, SNAI2, END3, and EDNRB genes were investigated through high-throughput sequencing. Based on the results of high-throughput sequencing, genetic variants in the patient and his family were verified and analyzed by Sanger sequencing.

RESULTS

The patient was diagnosed with typical WS1 that manifested in hearing impairment, inner canthus ectopia and heterochromic iris. Sanger sequencing revealed the pathogenic heterozygous c.420-424de1CGCGGinsTTAC mutation in the PAX3 gene in the proband, which is a frameshift mutation that changed the amino acid sequence of the PAX3 protein from AVCDRNTVPSV to YSVIETPCRQ* (* refers to a stop codon) from amino acids 141-151. The stop codon induced by this mutation resulted in the truncation of the PAX3 protein. The same mutation sites were also found in the mother and younger sister of the proband. No previous report of this mutation was found in the Human Gene Mutation Database.

CONCLUSION

The novel heterozygous c.420-424de1CGCGGinsTTAC mutation is the molecular pathological cause for WS1 in our patient. The clinical and genetic characterization of this family with WS1 elucidated the genetic heterogeneity of PAX3 in WS1. Moreover, the mutation detected in this case has expanded the database of PAX3 mutations.

PAX3 Confers Functional Heterogeneity in Skeletal Muscle Stem Cell Responses to Environmental Stress

Muscle satellite cells (MuSCs) are the quiescent muscle stem cells required for adult skeletal muscle repair. The impact of environmental stress such as pollution on MuSC behavior remains unexplored. We evaluated the impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure, a ubiquitous and highly toxic pollutant, on MuSCs by combining in vivo mouse molecular genetic models with ex vivo studies. While all MuSCs express the transcription factor PAX7, we show that a subset also express PAX3 and exhibit resistance to environmental stress. Upon systemic TCDD treatment, PAX3-negative MuSCs display impaired survival, atypical activation, and sporadic differentiation through xenobiotic aryl hydrocarbon receptor signaling. We further show that PAX3-positive MuSCs become sensitized to environmental stress when PAX3 function is impaired and that PAX3-mediated induction of mTORC1 is required for protection. Our study, therefore, identifies a functional heterogeneity of MuSCs in response to environmental stress controlled by PAX3.

MiR-1 Suppresses Proliferation of Osteosarcoma Cells by Up-regulating p21 via PAX3

BACKGROUND/AIM

miRNA-1(miR-1) is down-regulated in various cancer cells including osteosarcoma cells. This study was conducted to analyze the function of miR-1 in osteosarcoma cells.

MATERIALS AND METHODS

miR-1 expression in osteosarcoma cells was evaluated by qRT-PCR. Cell proliferation was evaluated after transfecting miR-1 by WST8 assay and FACS analysis, both in vitro and in vivo.

RESULTS

Overexpression of miR-1 suppressed cell proliferation and induced cell-cycle arrest in the G₀-G₁ phase by increasing p21 levels via a p53-independent pathway. Overexpression of miR-1 down-regulated PAX3, a potential p21-regulating gene. Moreover, knockdown of PAX3 suppressed cell proliferation by increasing p21 levels, and induced arrest at the G₀/G₁ phase. Administration of miR-1 showed an in vivo antitumor effect.

CONCLUSION

Overexpression of miR-1 suppressed cell proliferation and induced arrest in the G₀/G₁ phase by increasing p21 levels via a p53-independent pathway through PAX3 suppression. These results indicate that miR-1 could be a therapeutic target for osteosarcoma.

[Diagnostic challenge of biphenotypic sinonasal sarcoma]

Sinonasal biphenotypic sarcoma has recently been described and included in the 2017 WHO classification. It is a low-grade sarcoma which is characterized by PAX3 rearrangements. It remains a diagnostic challenge because of its scarcity, and its considerable histologic overlap with other cellular spindle cell neoplasms. The histologic features, the immunoprofile and the main differential diagnoses of sinonasal biphenotypic sarcoma are presented through a case.

PAX3 Promotes Proliferation of Human Glioma Cells by WNT/β-Catenin Signaling Pathways

The PAX3 (paired box 3) gene plays an important role in embryonic development, diseases, and cancer formation. Our preliminary studies have shown that PAX3 gene is upregulated in glioma cells, which is associated with a worse prognosis. Moreover, PAX3, by facilitating cell proliferation and invasion and inhibiting cell apoptosis, plays an oncogenic role in glioma. However, the specific molecular mechanism of PAX3 acting as an oncogene in glioma remains unclarified. In the present study, we have found that PAX3 overexpression was observed in high grade glioma and predicted a worse prognosis. PAX3 overexpression did not correlate significantly to IDH1 mutation and MGMT methylation. Moreover, the expression of PAX3 was positively correlated with that of β-catenin. In U87 glioma cells, PAX3 interacted with β-catenin, as was confirmed by CO-IP. Besides, PAX3 overexpression promoted cell proliferation and cell cycle progression, while it inhibited cell apoptosis by altering the expressions of important molecules associated with the Wnt signaling pathway, including β-catenin, Myc, VEGF, cyclinD1, MMP7, and Wnt1. In the meantime, it was also proved that PAX3 correlated to β-catenin through a negative regulatory mechanism with respect to the promotion of U87 glioma cell proliferation and cell cycle progression and inhibition of the cell apoptosis. Our experiment demonstrated the role of PAX3 in promoting glioma growth and development, possibly by interacting directly with β-catenin and regulating the Wnt signaling pathway.

A PAX3/BRN2 rheostat controls the dynamics of BRAF mediated MITF regulation in MITFhigh /AXLlow melanoma

The BRAF kinase and the MAPK pathway are targets of current melanoma therapies. However, MAPK pathway inhibition results in dynamic changes of downstream targets that can counteract inhibitor-action not only in during treatment, but also in acquired resistant tumours. One such dynamic change involves the expression of the transcription factor MITF, a crucial regulator of cell survival and proliferation in untreated as well as drug-addicted acquired resistant melanoma. Tight control over MITF expression levels is required for optimal melanoma growth, and while it is well established that the MAPK pathway regulates MITF expression, the actual mechanism is insufficiently understood. We reveal here, how BRAF through action on the transcription factors BRN2 and PAX3 executes control over the regulation of MITF expression in a manner that allows for considerable plasticity. This plasticity provides robustness to the BRAF mediated MITF regulation and explains the dynamics in MITF expression that are observed in patients in response to MAPK inhibitor therapy.

MicroRNA-206 Reduces Osteosarcoma Cell Malignancy In Vitro by Targeting the PAX3-MET Axis

PURPOSE

This study was undertaken to explore how miR-206 represses osteosarcoma (OS) development.

MATERIALS AND METHODS

Expression levels of miR-206, PAX3, and MET mRNA were explored in paired OS and adjacent tissue specimens. A patient-derived OS cell line was established. miR-206 overexpression and knockdown were achieved by lentiviral transduction. PAX3 and MET overexpression were achieved by plasmid transfection. Treatment with hepatocyte growth factor (HGF) was utilized to activate c-Met receptor. Associations between miR-206 and PAX3 or MET mRNA in OS cells were verified by AGO2-RNA immunoprecipitation assay and miRNA pulldown assay. OS cell malignancy was evaluated in vitro by cell proliferation, metastasis, and apoptosis assays. PAX3 and MET gene expression in OS cells was assayed by RT-qPCR and Western blot. Activation of PI3K-AKT and MAPK-ERK in OS cells were assayed by evaluating Akt1 Ser473 phosphorylation and total threonine phosphorylation of Erk1/2, respectively.

RESULTS

Expression levels of miR-206 were significantly decreased in OS tissue specimens, compared to adjacent counterparts, and were inversely correlated with expression of PAX3 and MET mRNA. miR-206 directly interacted with PAX3 and MET mRNA in OS cells. miR-206 overexpression significantly reduced PAX3 and MET gene expression in OS cells in vitro, resulting in significant decreases in Akt1 and Erk1/2 activation, cell proliferation, and metastasis, as well as increases in cell apoptosis, while miR-206 knockdown showed the opposite effects. The effects of miR-206 overexpression on OS cells were reversed by PAX3 or MET overexpression, but only partially attenuated by HGF treatment.

CONCLUSION

miR-206 reduces OS cell malignancy in vitro by targeting PAX3 and MET gene expression.

HOXD8/DIAPH2-AS1 epigenetically regulates PAX3 and impairs HTR-8/SVneo cell function under hypoxia

The present study aimed to unravel the molecular basis underlying PAX3 down-regulation, known to be involved in pre-eclampsia (PE) occurrence and development. Data obtained from databases suggested that Pax3 methylation levels in the promoter region are high in the placentas of PE patients. However, the expression of methylation-adjusting enzymes, including DNMT1, LSD1, and EZH2, did not change. Since lncRNAs enhance the function of methylation-related enzymes independently of expression, we selected three lncRNAs, RP11-269F21.2, DIAPH2-AS1, and RP11-445K13.2, predicted to interact with methylation-adjusting enzymes. Two transcription factors, HOXD8 and Lhx3, predicted to regulate the expression of lncRNAs, were also selected. Using RNA interference technology, HOXD8 and Lhx3 were found to positively regulate DIAPH2-AS1 and RP11-445K13.2 in HTR-8/SVneo cells. Chromatin immunoprecipitation assays determined that DIAPH2-AS1 recruited LSD1 to histone 3, increasing DNMT1 stability at H3. The HOXD8/DIAPH2-AS1 network regulated HTR-8/SVneo cell function under hypoxia by epigenetically regulating PAX3. This regulatory network may thus be responsible for PAX3 down-regulation in the placentas of PE patients.

Aberrant expressions of miRNA-206 target, FN1, in multifactorial Hirschsprung disease

Background

MicroRNAs (miRNAs) have been associated with the Hirschsprung disease (HSCR) pathogenesis, however, the findings are still inconclusive. We aimed to investigate the effect of miRNA-206 and its targets, fibronectin 1 (FN1), serum deprivation response (SDPR), and paired box 3 (PAX3) expressions on multifactorial HSCR in Indonesia, a genetically distinct group within Asia.

Methods

We determined the miRNA-206, FN1, SDPR and PAX3 expressions in both the ganglionic and aganglionic colon of HSCR patients and control colon by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

Twenty-one sporadic HSCR patients and thirteen controls were ascertained in this study. The miRNA-206 expression was up-regulated (2-fold) in the ganglionic colon and down-regulated (0.5-fold) in the aganglionic colon compared to the control group (ΔC_T 12.4 ± 3.0 vs. 14.1 ± 3.9 vs. 13.1 ± 2.7), but these differences did not reach significant levels (p = 0.48 and p = 0.46, respectively). Interestingly, the FN1 expression was significantly increased in both the ganglionic (38-fold) and aganglionic colon (18-fold) groups compared to the control group ΔC_T 5.7 ± 3.0 vs. 6.8 ± 2.3 vs. 11.0 ± 5.0; p = 0.001 and p = 0.038, respectively). Furthermore, the expressions of SDPR were similar in the ganglionic, aganglionic and control colon groups (ΔC_T 2.4 ± 0.6 vs. 2.2 ± 0.4 vs. 2.1 ± 0.6; p = 0.16 and p = 0.39, respectively), while no change was observed in the PAX3 expression between the ganglionic, aganglionic, and control colon groups (ΔC_T 3.8 ± 0.8 vs. 4.1 ± 0.8 vs. 3.7 ± 1.1; p = 0.83 and p = 0.44, respectively).

Conclusion

Our study is the first report of aberrant FN1 expressions in the colon of patients with HSCR and supplies further insights into the contribution of aberrant FN1 expression in the HSCR pathogenesis.

MicroRNA-362-3p Targets PAX3 to Inhibit the Development of Glioma through Mediating Wnt/β-Catenin Pathway

BACKGROUND

Glioma is identified as a broad category of brain and spinal cord tumors. MiR-362-3p is important in regulating the genesis of different cancers; however, the mechanism of miR-362-3p in the progression of glioma remains largely unknown.

OBJECTIVES

This study aimed to elucidate pathobiological functions of miR-362-3p by targeting PAX3 in glioma.

METHOD

qRT-PCR and western blotting were used to examine miR-362-3p and PAX3 expression in glioma tissues and cells. CCK-8 assay and transwell assays were used to examine the functions of miR-362-3p on human glioma. Two bioinformatics analysis software and luciferase reporter assay were performed to analyze the relationship between miR-362-3p and PAX3.

RESULTS

MiR-362-3p was downregulated, and PAX3 was upregulated in glioma tissues and cells. Functional assays revealed that ectopic expression of miR-362-3p inhibited glioma cell proliferation and migration. Further, PAX3 was confirmed as direct target gene of miR-362-3p, and downregulation of PAX3 reversed the suppressive effects of miR-362-3p in glioma. In addition, miR-362-3p also exhibited suppressive effect on epithelial-mesenchymal transition and Wnt/β-catenin pathway.

CONCLUSIONS

MiR-362-3p downregulation or PAX3 overexpression predicted poor prognosis in glioma. MiR-362-3p played a role in the suppressive effect on glioma by targeting PAX3 through suppressing Wnt/β-catenin pathway.

A rare case of nasal biphenotypic sino-nasal sarcoma in a young female

Introduction

We report a case of sino-nasal sarcoma (SNS) which is a rare malignant tumor that forms in the nasal structure and only a few cases that were reported in the literature.

Case report

The patient was a 35 years old woman. She presented with a history of right nasal obstruction from a couple of months at the time of presentation and recent attacks of epistaxis. Diagnosis of SNS was made after careful history taking, Computed tomography (CT) scan and confirmed by a secondary biopsy histology report that was done in Harvard Medical school. The patient underwent surgery and the mass was excised endoscopically. Her symptoms have improved significantly and after two years follow up there was no recurrence of the tumor.

Discussion and conclusion

In conclusion, Biphenotypic Sino-nasal sarcoma is a very rare and newly diagnosed entity. However, it should be kept in mind while dealing with any suspicious nasal masses in patients especially in females.

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Nasal biphenotypic sino-nasal sarcoma is a rare malignancy of the nasal cavity and only few cases were reported in the literature.

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It's usually found in young women with symptoms of nasal obstruction.

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The importance of this study is to emphasis the importance of keeping nasal biphenotypic sino-nasal sarcoma in the differential diagnosis when encountering a nasal mass as despite it being rare as early recognition and treatment will improve the outcome significantly as seen in our patient after two years follow up with no recurrence and improvement of her symptoms after early excision.

MicroRNA-485-5p attenuates cell proliferation in glioma by directly targeting paired box 3

MicroRNA-485-5p (miR-485-5p) has been reported to be involved in the development and progression of human cancers; however, its role in glioma remains unclear. In the present study, we found that miR-485-5p was significantly down-regulated in both glioma tissues and cell lines. Functional experiments indicated that enhanced expression of miR-485-5p attenuated glioma cell proliferation in vitro and in vivo, and induced glioma cells cycle arrest in G1. MiR-485-5p was found to directly bind to the 3'-UTR of paired box 3 (PAX3) and decrease its expression of protein level, which further inhibits the proliferation of glioma. The decreasing of PAX3 was found to lead to the accumulation of p-JNK. Mechanistic studies revealed that restoring the expression of PAX3 alleviated miR-485-5p-induced inhibition of proliferation of glioma cells. Taken together, these findings suggest that PAX3 modulation by miR-485-5p has an important role in regulating glioma proliferation, and miR-485-5p might be a novel therapeutic target for glioma.

First report of Klein-Waardenburg Syndrome in Iran and a novel pathogenic splice site variant in PAX3 gene

OBJECTIVES

Waardenburg Syndrome (WS) as a congenital auditory-pigmentary syndrome is a clinically and genetically heterogeneous disorder. Based upon clinical manifestations, it can be classified into four types. Loss of function mutations in PAX3 gene cause WS1 and WS3 (Klein-Waardenburg syndrome). While WS2 and WS4 have locus heterogeneity with multiple causative genes. Here we report a novel splice site variant in a pedigree with multiple affected members. Based on diagnostic criteria, three of them are associated with WS3. The remained patients classified as type 1.

METHODS

PCR amplification and Sanger sequencing were performed for all exons and all exon-intron boundaries of PAX3 (NM_181,459) gene of the proband. Then available symptomatic and asymptomatic members were screened for the detected variant. Interpretation and classification of the variant were done based on the current guidelines.

RESULTS

We identified a novel heterozygous splice site variant (c.586+2T > C) in donor site of intron 4 of PAX3 gene in our proband. Moreover, this variant was co-segregated with the disease in other available five affected members. Also, the detected variant was not detected in any of the investigated asymptomatic members. This variant was classified as a pathogenic variant.

CONCLUSIONS

This study shows significant intra-familial clinical heterogeneity and absence of phenotype-genotype correlation in a pedigree with Waardenburg Syndrome. However, severity of phenotypes and additional symptoms in the patients can be related to alternative splicing and different levels of PAX3 gene expression. Detailed evaluation of more cases can shed light on this and case-reports are valuable traffic sign in the road. This article is the first report of Waardenburg syndrome type 3 in Iran.

Transcriptional Repression of p53 by PAX3 Contributes to Gliomagenesis and Differentiation of Glioma Stem Cells

Although there are available therapies as surgery, chemotherapy and radiation, glioblastoma (GBM) still has been considered as the most common and overwhelming primary tumor of brain. In GBM, the brain glioma stem cells (BGSCs) were identified and played a crucial role in resistance of GBM to conventional therapies described above. PAX3 was previously identified by our group as a diagnostic/prognostic marker and a therapeutic regulator in the therapy of GBM. Here, we hypothesized PAX3/p53 axis promoted the process of differentiation, regulating to the cancer stem cell properties, such as proliferation and migration. The correlation between PAX3 and p53 in GBM were first clarified. Immunofluorescence of p53 was shown activated following BGSCs differentiation. We further identified that PAX3 might specifically bind to the promoter of p53 gene, and transcriptionally repressed p53 expression. ChIP assay further confirmed that PAX3/p53 axis regulated the differentiation process of BGSCs. Then, the function of PAX3 in BGSCs were sequentially investigated in vitro and in vivo. Ectopic PAX3 expression promoted BGSCs growth and migration while PAX3 knockdown suppressed BGSCs growth, migration in vitro and in vivo. Similar to PAX3 overexpression, p53 inhibition also showed increase in growth and migration of differentiated BGSCs. Regarding the functional interaction between PAX3 and p53, PAX3 knockdown-mediated decrease in proliferation was partially rescued by p53 inhibition. Hypoxia significantly promoted the migration potential of BGSCs. In addition, hypoxia inducible factor-1α (HIF-1α) might be a potential upstream regulator of PAX3 in differentiated BGSCs under hypoxia. Our work may provide a supplementary mechanism in regulation of the BGSCs differentiation and their functions, which should provide novel therapeutic targets for GBM in future.

The regulation of survival and differentiation of neural stem cells by miR-124 via modulating PAX3

MicroRNAs (miRNAs) have crucial functions in the regulation of proliferation and differentiation of neural stem cells (NSCs). MiR-124 has been reported to be implicated in neurogenesis. However, the precise function and mechanism of miR-124 still need further verification. In this study, we identified paired box 3 (PAX3) as a potential target of miR-124 using bioinformatics approaches. Next, we found PAX3 had reversed expression pattern with miR-124 as well as TUBB3 and GFAP. Dual-luciferase assay showed that miR-124 could bind to the 3'-UTR of PAX3 mRNA and restrain its expression. It was demonstrated that overexpression and knocking down of miR-124 in NSCs could promote the survival and suppress the apoptosis of NSCs. Meanwhile, miR-124 enhanced the expression of TUBB3 and GFAP via impairing PAX3 expression. Mechanistic study revealed that augmented Akt-GSK3β signaling pathway was the driving-force for the regulatory functions of miR-124 in NSCs. In summary, this study for the first time uncovered that miR-124 could suppress PAX3 expression, which in turn regulated the differentiation of NSCs.

Developmentally linked human DNA hypermethylation is associated with down-modulation, repression, and upregulation of transcription

DNA methylation can affect tissue-specific gene transcription in ways that are difficult to discern from studies focused on genome-wide analyses of differentially methylated regions (DMRs). To elucidate the variety of associations between differentiation-related DNA hypermethylation and transcription, we used available epigenomic and transcriptomic profiles from 38 human cell/tissue types to focus on such relationships in 94 genes linked to hypermethylated DMRs in myoblasts (Mb). For 19 of the genes, promoter-region hypermethylation in Mb (and often a few heterologous cell types) was associated with gene repression but, importantly, DNA hypermethylation was absent in many other repressed samples. In another 24 genes, DNA hypermethylation overlapped cryptic enhancers or super-enhancers and correlated with down-modulated, but not silenced, gene expression. However, such methylation was absent, surprisingly, in both non-expressing samples and highly expressing samples. This suggests that some genes need DMR hypermethylation to help repress cryptic enhancer chromatin only when they are actively transcribed. For another 11 genes, we found an association between intergenic hypermethylated DMRs and positive expression of the gene in Mb. DNA hypermethylation/transcription correlations similar to those of Mb were evident sometimes in diverse tissues, such as aorta and brain. Our findings have implications for the possible involvement of methylated DNA in Duchenne's muscular dystrophy, congenital heart malformations, and cancer. This epigenomic analysis suggests that DNA methylation is not simply the inevitable consequence of changes in gene expression but, instead, is often an active agent for fine-tuning transcription in association with development.