Identification of a Novel Homozygous Mutation in MTMR2 Gene Causes Very Rare Charcot-Marie-Tooth Disease Type 4B1.

Background: Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of disorders involving peripheral nervous system. Charcot-Marie-Tooth disease 4B1 (CMT4B1) is a rare subtype of CMT. CMT4B1 is an axonal demyelinating polyneuropathy with an autosomal recessive mode of inheritance. Patients with CMT4B1 usually manifested with dysfunction of the motor and sensory systems which leads to gradual and progressive muscular weakness and atrophy, starting from the peroneal muscles and finally affecting the distal muscles. Germline mutations in MTMR2 gene causes CMT4B1. Material and Methods: In this study, we investigated a 4-year-old Chinese boy with gradual and progressive weakness and atrophy of both proximal and distal muscles. The proband's parents did not show any abnormalities. Whole-exome sequencing and Sanger sequencing were performed. Results: Whole-exome sequencing identified a novel homozygous nonsense mutation (c.118A>T; p.Lys40*) in exon 2 of MTMR2 gene in the proband. This novel mutation leads to the formation of a truncated MTMR2 protein of 39 amino acids instead of the wild- type MTMR2 protein of 643 amino acids. This mutation is predicted to cause the complete loss of the PH-GRAM domain, phosphatase domain, coiled-coil domain, and PDZ-binding motif of the MTMR2 protein. Sanger sequencing revealed that the proband's parents carried the mutation in a heterozygous state. This mutation was absent in 100 healthy control individuals. Conclusion: This study reports the first mutation in MTMR2 associated with CMT4B1 in a Chinese population. Our study also showed the importance of whole-exome sequencing in identifying candidate genes and disease-causing variants in patients with CMT4B1.

Identification of a novel homozygous loss-of-function mutation in FUCA1 gene causing severe fucosidosis: A case report.

Fucosidosis is a rare lysosomal storage disorder characterized by deficiency of α-L-fucosidase with an autosomal recessive mode of inheritance. Here, we describe a 4-year-old Chinese boy with signs and symptoms of fucosidosis but his parents were phenotypically normal. Whole exome sequencing (WES) identified a novel homozygous single nucleotide deletion (c.82delG) in the exon 1 of the FUCA1 gene. This mutation will lead to a frameshift which will result in the formation of a truncated FUCA1 protein (p.Val28Cysfs*105) of 132 amino acids approximately one-third the size of the wild type FUCA1 protein (466 amino acids). Both parents were carrying the mutation in a heterozygous state. This study expands the mutational spectrum of the FUCA1 gene associated with fucosidosis and emphasises the benefits of WES for accurate and timely clinical diagnosis of this rare disease.

Identification of differentially expressed circular RNAs in human nasopharyngeal carcinoma.

BACKGROUND: Circular RNAs (circRNAs) are endogenous RNAs that have a covalent closed cycle configuration. circRNAs have been found to be differentially expressed in many human cancers. Therefore, circRNAs may be ideal biomarkers for the diagnosis and treatment of cancer. However, we know very little about the function of circRNAs in nasopharyngeal carcinoma (NPC). The purpose of this study was to evaluate the circRNA expression profiles in NPC. METHODS: We utilized high-throughput RNA sequencing (RNA-Seq) to evaluate the circRNA expression profile in NPC A total of 13,561 unique circRNA candidates were detected. Selection of aberrantly expressed circRNAs was carried out using a q-value of < 0.001 with a fold change of > 2.0 or < 0.5. We carried out Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses to identify the biological functions of differentially expressed circRNAs. Moreover, bioinformatics analyses were implemented to predict the effects between circRNAs and cancer-related microRNAs (miRNAs), and we used Cytoscape to build a cancer-related circRNA-miRNA target gene map. Finally, to verify dysregulated circRNAs, quantitative real-time PCR was utilized. RESULTS: In NPC tissues, we found that 73 circRNAs were downregulated and 59 were upregulated. The top 12 candidate circRNAs were selected from several vital NPC pathways such as the human papillomavirus and Epstein-Barr virus infection signaling pathways (hsa05165 and hsa05169, respectively), Hepatitis B (hsa05161), and the Ras signaling pathway (hsa04014). A network map of circRNA-miRNA interactions of 12 differentially expressed circRNAs was built. Hsa_circ_0007637 expression distinguished NPC tissues from paired healthy tissues and NPC cell lines (HNE1 6-10B, 5-8F, CNE-2, and so on) from a normal epithelial (NP460) cell line. CONCLUSIONS: In this study, we investigated the profiles of differentially expressed circRNAs in NPC, and our results show that hsa_circ_0007637 may be a biomarker for NPC and play a role in its development. This observation-based research identified dysregulated circRNAs in NPC, which may assist in the development of biomarkers for this disease. Further studies on the mechanisms and functions of these circRNAs may promote our understanding of NPC tumorigenesis.

Long non-coding RNA ZNF674-1 acts as a cancer suppressor in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is the most frequently occurring carcinoma of the head and neck. The complexity of NPC makes it difficult for it to be diagnosed and treated at an early stage. Certain long non-coding RNAs (lncRNAs) are closely associated with the carcinogenesis of NPC. In the present study, the expression of lncRNA ZNF674-1 in NPC tissues and an NPC cell line was analyzed and was revealed to be downregulated compared with normal tissues and cells. When the expression of lncRNA ZNF674-1 was reduced in NPC cells, the proliferation, migration and invasion of these cells was promoted, whereas the apoptosis of these cells was decreased. On the contrary, when overexpressed, the expression of lncRNA ZNF674-1 inhibited the proliferation, invasion and migration of cells, but promoted cell apoptosis. The results of the present study reveal that the lncRNA ZNF67-1 may restrain the carcinogenesis of NPC, and may also serve as a potential biomarker for the early diagnosis and treatment of NPC.

lncRNA C22orf32-1 contributes to the tumorigenesis of nasopharyngeal carcinoma.

The mechanism of nasopharyngeal carcinoma (NPC) remains unclear. The present study investigated the abnormal expression of long non-coding (lnc)RNAs in NPC tissues and one NPC cell line to identify the involvement of lncRNAs in the tumorigenesis of NPC. Using a quantitative reverse transcription polymerase chain reaction (RT-qPCR), the expression of lncRNA C22orf32-1 in NPC tissues and an NPC cell line was verified. The effects of lncRNA C22orf32-1 on NPC cells were investigated with a cell proliferation assay, cell scratch assay, Transwell assay and a cell apoptosis assay. The expression levels of lncRNA C22orf32-1 in NPC tissues and an NPC cell line were upregulated. lncRNA C22orf32-1 promoted the proliferation, migration and invasion of NPC cells, and reduced the apoptosis of NPC cells. The data demonstrated that lncRNA C22orf32-1 may facilitate the tumorigenesis of NPC, and may be used for the early diagnosis and treatment of NPC.

miR­30a­5p in the tumorigenesis of renal cell carcinoma: A tumor suppressive microRNA.

Renal cell carcinoma (RCC) is the most common type of malignant tumor of the adult kidney and has a poor prognosis. MicroRNAs (miRs) are important in a wide range of biological and pathological processes, including cell differentiation, migration, growth, proliferation, apoptosis and metabolism. The present study aimed to determine the role exerted by miR­30a­5p in the tumorigenesis of RCC. The expression levels of miR­30a­5p in RCC tissues and RCC­derived cells were demonstrated to be significantly downregulated by real­time quantitative polymerase chain reaction (RT­qPCR). Wound scratch assay, cell proliferation assay and flow cytometric analysis revealed that the abilities of migration and proliferation of the RCC­derived cells were suppressed, whereas cell apoptosis was promoted, when miR­30a­5p was overexpressed in these cells. N­acetylgalactosaminyltransferase 7 (GALNT7) was predicted to be one target gene of miR­30a­5p by bioinformatics analysis. Luciferase reporter assay, RT­qPCR and western blotting were performed to confirm that GALNT7 is the direct conserved target of miR­30a­5p. These results suggested that miR­30a­5p has a tumor­suppressive role in the tumorigenesis of RCC.

GALNT7, a target of miR-494, participates in the oncogenesis of nasopharyngeal carcinoma.

GalNAc-transferase-7 (GALNT7) is essential for the regulation of cell proliferation and has been implicated in tumorigenesis. However, the role of GALNT7 in the development and progression of nasopharyngeal carcinoma (NPC) remains unclear. Our previous study showed that GALNT7 was a putative target of miR-494, which was confirmed by luciferase reporter assay. In the present study, we demonstrated that in vitro knockdown of GALNT7 significantly inhibited the proliferation, colony formation, migration, and invasion of NPC-derived cells. In vivo tumorigenicity assay showed that miR-494 and GALNT7-small interfering RNA (siRNA) reduced tumor growth in nude mice. Taken together, our results provided new evidence for an oncogenic role of GALNT7 in NPC.

MicroRNA­205 promotes the tumorigenesis of nasopharyngeal carcinoma through targeting tumor protein p53-inducible nuclear protein 1.

Nasopharyngeal carcinoma (NPC) is a common type of cancer in southern China, miRNAs have been shown to be involved in the tumorigenesis of multiple cancer types. The present study aimed to explore the potential role of miR­205 in NPC. Reverse transcription quantitative polymerase chain reaction was used to determine the expression levels of miR­205 in 20 fresh NPC specimens and 20 normal nasopharyngeal tissues. The function of miR­205 in the proliferation, migration, invasion and apoptosis of NPC­derived cells was detected by MTT assay, colony formation assay, wound healing assay, Transwell assay and flow cytometry. Furthermore, a target gene of miR­205 was identified using the luciferase reporter assay. The expression of miR­205 was increased in NPC tissues compared with that in normal tissues. Overexpression of miR­205 was found to promote the proliferation, migration and invasion of NPC­derived cells, while apoptosis was suppressed. Tumor protein p53-inducible nuclear protein 1 was identified as a target gene of miR­205. Overall, the present study demonstrated that miR­205 may function as an oncogene in NPC tumorigenesis.

Functional elucidation of miR-494 in the tumorigenesis of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma has very high incidence and high mortality worldwide. MiRNA is related to the tumorigenesis and metastasis of a variety of tumors. In the present study, we verify that the expression of miR-494 in NPC tissues and NPC-derived cells was down-regulated, respectively. The proliferation, colony formation, migration, and invasion of NPC-derived cells were suppressed, while the cell apoptosis was promoted, when miR-494 was over-expressed in these cells. GALNT7 and CDK16 were confirmed to be the direct targets of miR-494. These results suggested that miR-494 play an inhibitory role in the tumorigenesis of NPC.

[Idenfication of microRNAs profiles in nasopharyngeal carcinoma].

OBJECTIVE: To filtrate and prove the different microRNAs (miRs) profiles in nasopharyngeal carcinoma. METHOD: Screening the different expressions of miRs between nasopharyngeal carcinoma and the inflammatory tissues by the application of expression profiling of chip high-throughput and large-scale microarray analysis. Then we used RT-QPCR technology to prove the accuracy of screening results. RESULT: There were significant expression differences of miRs between nasopharyngeal carcinoma and the control tissues, 144 human miRs had 2 or more fold the difference ratio. Compared with the inflammatory tissues, we have found that miRs-34b, miRs-449b and miRs-7-1 significantly low expressed in nasopharyngeal carcinoma, yet miRs-125b, miRs-184, miRs-196b, miRs-205 and miRs-24-1 expressed high. The results were consistent with the microarray analysis. CONCLUSION: The difference expressed miRs might be closely related to the process of nasopharyngeal carcinoma, and the research on miRs profiles maybe provide a powerful target basis for early diagnosis and therapy of nasopharyngeal carcinoma.