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Accumulating evidence has demonstrated that circular RNAs (circRNAs) play important roles in regulating gene expression involved in tumor development. However, the role of circRNAs in modulating the radiosensitivity of oral squamous cell carcinoma (OSCC) and its potential mechanisms have not been documented. We performed high-throughput RNA sequencing (RNA-seq) to investigate the circRNA expression profile in OSCC patients and discovered that the circATRNL1 expression was significantly downregulated and closely related to tumor progression. The circATRNL1 was structurally validated via Sanger sequencing, RNase R treatment, and specific convergent and divergent primer amplification. Importantly, the expression levels of circATRNL1 decreased after irradiation treatment, and upregulation of circATRNL1 enhanced the radiosensitivity of OSCC through suppressing proliferation and the colony survival fraction, inducing apoptosis and cell-cycle arrest. Moreover, we observed that circATRNL1 could directly bind to microRNA-23a-3p (miR-23a-3p) and relieve inhibition for the target gene PTEN. In addition, the tumor radiosensitivity-promoting effect of circATRNL1 overexpression was blocked by miR-23a-3p in OSCC. Further experiments also showed that PTEN can reverse the inhibitory effect of OSCC radiosensitivity triggered by miR-23a-3p. We concluded that circANTRL1 may function as the sponge of miR-23a-3p to promote PTEN expression and eventually contributes to OSCC radiosensitivity enhancement. This study indicates that circANTRL1 may be a novel therapeutic target to improve the efficiency of radiotherapy in OSCC.

Summary Cisplatin-based neoadjuvant chemotherapy has been shown to improve survival in patients with squamous cell carcinoma (SCC), but clinical biomarkers to predict chemosensitivity remain elusive. Here, we show the long noncoding RNA (lncRNA) LINC01011, which we termed cisplatin-sensitivity-associated lncRNA (CISAL), controls mitochondrial fission and cisplatin sensitivity by inhibiting BRCA1 transcription in tongue SCC (TSCC) models. Mechanistically, we found CISAL directly binds the BRCA1 promoter and forms an RNA-DNA triplex structure, sequestering BRCA1 transcription factor-GABPA away from the downstream regulatory binding region. Importantly, the clinical relevance of these findings is suggested by the significant association of CISAL and BRCA1 expression levels in TSCC tumors with neoadjuvant chemosensitivity and overall survival. We propose a new model where lncRNAs are tethered at gene promoter by RNA-DNA triplex formation, spatially sequestering transcription factors away from DNA-binding sites. Our study uncovers the potential of CISAL-BRCA1 signaling as a potential target to predict or improve chemosensitivity., Graphical Abstract, Highlights • CISAL enhances mitochondrial fission and cisplatin sensitivity in TSCC cells through BRCA1 • CISAL directly binds the BRCA1 promoter and forms an RNA-DNA triplex structure • CISAL sequesters GABPA away from regulatory binding at BRCA1 promoter • High CISAL predicts favorable neoadjuvant chemosensitivity and prognosis of TSCC patients, Biological Sciences; Molecular Biology; Cell Biology; Cancer

Osteopetrosis is a group of heterogeneous disorders caused by the dysfunction of osteoclasts. The CLCN7 and TCIRG1 genes are the major obligate genes responsible for infantile malignant osteopetrosis (IMO). IMO patients usually die in infancy or before three years of age. In this study, we report a patient who was diagnosed with IMO at seven months of age. The patient presented with classical radiological features of IMO. She also exhibited erythropenia, thrombocytopenia, hepatosplenomegaly and neurodegeneration. The parents discontinued any medical treatment for the patient. Surprisingly, the patient's condition did not deteriorate when she was admitted a second time at the age of four years and nine months, despite not receiving any medical support during the untreated period. We sequenced the CLCN7 and TCIRG1 genes of the patient and her parents and identified a novel c.285+1G>A (IVS3+1G>A) mutation and the known c.896C>T (p.Ala299Val) mutation. The novel c.285+1G>A mutation occurred on the splice donor of the third intron of CLCN7. This mutation was predicted to interfere with normal splicing between exons 3 and 4, thereby truncating 711 amino acids from the C terminus and resulting in the loss of all of the functional domains of the encoded protein. The c.896C>T (p.Ala299Val) mutation was a previously known pathogenic mutation. We did not find any pathogenic mutations in the TCIRG1 gene. CLCN7-related osteopetrosis is known to have a high phenotype heterogeneity. Our study demonstrates a wide heterogeneity in the progression of the phenotypes and expanded the mutational spectrum for the CLCN7 gene.

Objective Tooth agenesis (TA) is featured by congenital loss of teeth, and can be divided into two subtypes, non-syndromic TA (NSTA) and syndromic TA (STA). Although 12 candidate genes of NSTA have been revealed, the genetic basis of NSTA needs to be further studied. We noticed an overlap of candidate genes between NSTA and STA, and hypothesized that some candidate genes of STA may be new candidate genes of NSTA. Methods Sanger sequencing, whole exome sequencing, bioinformatics analyses and immunohistochemical staining were performed to reveal the genetic basis of the patients in a family with NSTA. Results No pathogenic mutation was found in the 12 candidate genes of NSTA. We screened the variants of 76 STA candidate genes and identified a novel pathogenic mutation c.G908C (p.R303 P) in Keratinocyte Differentiation Factor 1 (KDF1). This mutation was cosegregated with the disease in the family. Bioinformatics analyses predicted the mutation to be pathogenic. Immunohistochemical staining of kdf1 in developing tooth germs indicated that kdf1 expression is important for the development of teeth. Conclusions This study identified KDF1 as a novel candidate gene for NSTA. STA candidate genes may be a promising source of new NSTA genes.

SLC10A1 codes for the sodium-taurocholate cotransporting polypeptide (NTCP), which is a hepatocellular transporter for bile acids (BAs) and the receptor for hepatitis B and D viruses. NTCP is also a target of multiple drugs. We aimed to evaluate the medical consequences of the loss of function mutation p.Ser267Phe in SLC10A1. We identified eight individuals with homozygous p.Ser267Phe mutation in SLC10A1 and followed up for 8–90 months. We compared their total serum BAs and 6 species of BAs with 170 wild-type and 107 heterozygous healthy individuals. We performed in-depth medical examinations and exome sequencing in the homozygous individuals. All homozygous individuals had persistent hypercholanemia (P = 5.8 × 10–29). Exome sequencing excluded the involvement of other BA metabolism-associated genes in the hypercholanemia. Although asymptomatic, all individuals had low vitamin D levels. Of six adults that were subjected to bone mineral density analysis, three presented with osteoporosis/osteopenia. Sex hormones and blood lipids were deviated in all subjects. Homozygosity of p.Ser267Phe in SLC10A1 is associated with asymptomatic hypercholanemia. Individuals with homozygous p.Ser267Phe in SLC10A1 are prone to vitamin D deficiency, deviated sex hormones and blood lipids. Surveillance of these parameters may also be needed in patients treated with drugs targeting NTCP.

BACKGROUND: Gnathodiaphyseal dysplasia (GDD) is a rare skeletal disorder that has not been well studied. METHODS: Sanger sequencing, whole-genome sequencing, and bioinformatics and structural modeling analyses were performed. RESULTS: A family with patients with fibro-osseous lesions of the jawbones were initially diagnosed with cherubism. Sequencing of SH3BP2, which is the causal gene of cherubism, revealed no pathogenic mutation. Through whole-genome sequencing, we identified a novel mutation c.1067G>T (p.C356F) in ANO5, and bioinformatics analyses and structural modeling showed that the mutation was deleterious. Because ANO5 is the gene responsible for GDD, we reappraised the clinical data of the patients, and the diagnosis was corrected to atypical GDD. A review of the literature showed that 67% of GDD cases confirmed by molecular testing were initially misdiagnosed. CONCLUSIONS: The novel mutation c.1067G>T (p.C356F) in ANO5 is responsible for the atypical GDD observed in our patients. GDD should be included in the differential diagnosis for patients with fibro-osseous lesions.

Hypohidrotic ectodermal dysplasia (HED) is characterized by abnormal development of the teeth, hair, and sweat glands. Ectodysplasin A (EDA), Ectodysplasin A receptor (EDAR), and EDAR-associated death domain (EDARADD) are candidate genes for HED, but the relationship between WNT10A and HED has not yet been validated. In this study, we included patients who presented at least two of the three ectodermal dysplasia features. The four genes were analyzed in seven HED patients by PCR and Sanger sequencing. Five EDA and one EDAR heterozygous mutations were identified in families 1–6. Two WNT10A heterozygous mutations were identified in family 7 as a compound heterozygote. c.662G>A (p.Gly221Asp) in EDA and c.354T>G (p.Tyr118*) in WNT10A are novel mutations. Bioinformatics analyses results confirmed the pathogenicity of the two novel mutations. In family 7, we also identified two single-nucleotide polymorphisms (SNPs) that were predicted to affect the splicing of EDAR. Analysis of the patient’s total RNA revealed normal splicing of EDAR. This ascertained that the compound heterozygous WNT10A mutations are the genetic defects that led to the onset of HED. Our data revealed the genetic basis of seven HED patients and expended the mutational spectrum. Interestingly, we confirmed WNT10A as a candidate gene of HED and we propose WNT10A to be tested in EDA-negative HED patients.