Hsi-Yuan Huang

DNA-Sensing and Nuclease Gene Expressions as Markers for Colorectal Cancer Progression

Objective: Oncogene-driven stress-related DNA damage has been observed in lesions of colon cancer. Furthermore, DNA sensors and nucleases are stimulated during active DNA damage and replication. However, their changes and influences with respect to cancer remain largely unknown. Methods: The gene expression levels of cGAS, IFI16, STING, TBK1, IFNB1, TREX1, SAMHD1, RNASEH2A, RNASEH2B, and RNASEH2C were examined in the paired colorectal cancer and adjacent normal part tissues of 53 patients. Their associations with the clinical stages of cancer were then analyzed. Results: All cytosolic DNA-sensing and nuclease-related genes except cGAS, RNASEH2A, and RNASEH2B showed lower mRNA expressions in the colorectal tumor tissues. Moreover, cGAS upregulation was found to be associated with early-stage colorectal cancers, while higher expressions of RNASEH2B, RNASEH2C, and SAMHD1 correlated with metastasis. RNASEH2C knockdown in a colon cancer cell line impaired cell migration, and analysis of the cancer RNA-seq data from The Cancer Genome Atlas (TCGA) database revealed a negative correlation between RNASEH2C expression and E-cadherin levels. Conclusions: In contrast to DNA-sensing events in viral infections or autoimmunity, cGAS-STING-IFNB signaling is disrupted in colorectal cancer. The expression levels of cGAS, RNASEH2B, RNASEH2C, and SAMHD1 could be prognostic markers of colorectal cancer.

Antimicrobial effects of Ag/TiO 2 compound coatings and ZnO films on titanium based surface

Nano Ag/TiO2 compound coatings and zinc oxide films were used to enhance the capacity of antibacterial ability and maintain the functions of gingival fibroblast cells for the titanium (Ti) based dental implant. Various Ag/TiO2 compound coatings were deposited on the Ti plate samples by a sputtering process with different power for creating the coatings with different ratios of Ag/TiO2. Zinc oxide films with different thicknesses were electroplated. The hydrophilicity of the samples was examined by measuring the contact angle. Streptococcus mutans were cultured on nanoparticle coated samples and determined the antibacterial effects using a standard Syto9 fluorescent staining method. The outcomes of the zinc oxide samples’ contact angle did not show an identical tendency. While more ZnO were coated on the Ti plate, the antibacterial effect was more efficient. As for the nano Ag/TiO2 samples, the more watt used to deposited silver on the plate, representing more Ag/TiO2 quantity coated on the samples, the greater the contact angle were, and also stood for more hydrophobic characteristic. Streptococcus mutans formed the least bacterial numbers on the 50W nano Ag/TiO2 deposited plates, which contained the greatest amount of Ag among all the nano Ag/TiO2 samples.

Whole exome sequencing in Dandy-Walker variant with intellectual disability reveals an activating CIP2A mutation as novel genetic cause

Dandy-Walker malformation (DWM) has been reported to have heterogeneous causes, including mutations in genes of fibroblast growth factors and in genes in the sonic hedgehog (Shh) signaling pathway. Here, we identified an activating cancerous inhibitor of protein phosphatase 2A (CIP2A) p.D269V mutation, located at the predicted protein-protein interaction groove, as a novel genetic cause of Dandy-Walker variant (DWV). CIP2A has been reported as an oncoprotein promoting tumor survival via inhibition of protein phosphatase 2A (PP2A). However, the impact of human germline CIP2A mutation is unknown. We report a novel heterozygous CIP2A p.D269V mutation via whole exome sequencing in two siblings with DWV and severe intellectual disability who were born to non-consanguineous parents. Only the older brother developed a slow-growing sacral leiomyoma in his teens. The CIP2A p.D269V mutation is associated with increased PP2A, mTOR, and c-Myc protein levels in peripheral blood mononuclear cells (PBMCs). The PP2A phosphatase activity, however, was not suppressed. Deep sequencing revealed that the father carries 16% of somatic CIP2A p.D269V mutation, suggesting potential inheritance from the mosaic sperm populations. Our study is the first to describe a pathogenic CIP2A mutation in humans, which might disrupt neuronal development via enhancing mTOR and c-Myc protein expressions, shedding light in mechanisms of DWV pathogenesis.

G6PD as a predictive marker for glioma risk, prognosis and chemosensitivity

PurposeGlucose-6-phosphate dehydrogenase (G6PD) is a key enzyme preventing cells from oxidative damage and has been reported to have tumor-promoting roles. This study aims to comprehensively evaluate the predictive values of G6PD on brain tumor risk, prognosis and chemo-resistance.MethodsA retrospective 13-year cohort study analyzing cancer risk using the Taiwan National Health Insurance Research Database (4066 G6PD deficiency patients and 16,264 controls) was conducted. Furthermore, RNAseq and clinical data of grade II–III glioma (LGG, n = 515) and glioblastoma (GBM, n = 155) were downloaded from The Cancer Genome Atlas (TCGA) and analyzed. Bioinformatics methods were applied to build a glioma prognostication model and to predict response to chemotherapy based on tumor G6PD-related gene expressions. The predicted results were validated in another glioma cohort GSE 16011 and in KALS1 cell line.ResultsG6PD-dificient patients were found to have an increased risk for cancers, especially for brain tumor (adjusted hazard ratio (HR) 10.5, 95% CI 1.03–7.60). Furthermore, higher tumor G6PD expression was associated with poor patient survival in LGG, but not in GBM. A prognostication model using expression levels of G6PD and 9 related genes (PSMA2, PSMB8, SHFM1, GSS, GSTK1, MGST2, POLD3, MSH2, MSH6) could independently predict LGG patient survival. Boosted decision tree analysis on 213 cancer cell line database revealed predictive values of G6PD expression on response to gemcitabine and bortezomib. Knockdown of G6PD in KALS1 cell line enhanced its sensitivity to both chemotherapeutic agents.ConclusionsOur study suggests that G6PD could be a marker predicting glioma risk, prognosis and chemo-sensitivity.

Correlation of genomic alterations between tumor tissue and circulating tumor DNA by next-generation sequencing

PurposeAnalysis of circulating tumor DNA (ctDNA) offers an unbiased and noninvasive way to assess the genetic profiles of tumors. This study aimed to analyze mutations in ctDNA and their correlation with tissue mutations in patients with a variety of cancers.MethodsWe included 21 cancer patients treated with surgical resection for whom we collected paired tissue and plasma samples. Next-generation sequencing (NGS) of all exons was performed in a targeted human comprehensive cancer panel consisting of 275 genes.ResultsSix patients had at least one mutation that was concordant between tissue and ctDNA sequencing. Among all mutations (n = 35) detected by tissue and blood sequencing, 20% (n = 7) were concordant at the gene level. Tissue and ctDNA sequencing identified driver mutations in 66.67% and 47.62% of the tested samples, respectively. Tissue and ctDNA NGS detected actionable alterations in 57.14% and 33.33% of patients, respectively. When somatic alterations identified by each test were combined, the total proportion of patients with actionable mutations increased to 71.43%. Moreover, variants of unknown significance that were judged likely pathogenic had a higher percentage in ctDNA exclusively. Across six representative genes (PIK3CA, CTNNB1, AKT1, KRAS, TP53, and MET), the sensitivity and specificity of detection using mutations in tissue sample as a reference were 25 and 96.74%, respectively.ConclusionsThis study indicates that tissue NGS and ctDNA NGS are complementary rather than exclusive approaches; these data support the idea that ctDNA is a promising tool to interrogate cancer genetics.

Prognostic Value of RNASEH2A-, CDK1-, and CD151-Related Pathway Gene Profiling for Kidney Cancers

The nucleotide degrading enzyme gene RNASEH2A (ribonuclease H2 subunit A) has been found to be overexpressed in cancers. Our aim was to understand the role of RNASEH2A in cancer prognostication and to establish a scoring system based on the expressions of genes interacting with RNASEH2A. We screened the nucleotide degrading enzyme gene expression in RNAseq data of 14 cancer types derived from The Cancer Genome Atlas (TCGA) and found that RNASEH2A overexpression was associated with poor patient survival only in renal cell carcinomas (RCCs). Further cluster analyses of samples with poor outcomes revealed that cluster of differentiation 151 (CD151) upregulation correlated with low cyclin dependent kinase 1 (CDK1) and high RNASEH2A expression. The combination of low CD151 expression and high RNASEH2A expression resulted in impaired proliferation in four kidney cancer cell lines, suggesting potential synthetic dosage lethality (SDL) interactions between the two genes. A prognostication scoring system was established based on the expression levels of RNASEH2A-, CDK1-, and CD151-related genes, which could effectively predict the overall survival in a TCGA clear cell RCC cohort (n = 533, 995.3 versus 2242.2 days, p < 0.0001), in another clear cell renal cell carcinoma (ccRCC) cohort E-GEOD-22541 (n = 44, 390.0 versus 1889.2 days, p = 0.0007), and in a TCGA papillary RCC (pRCC) cohort (n = 287, 741.6 versus 1623.7 days, p < 0.0001). Our results provide a clinically applicable prognostication scoring system for renal cancers.

Determination of the mutational landscape in Taiwanese patients with papillary thyroid cancer by whole-exome sequencing

Among women in Taiwan, thyroid cancer is the fifth most common malignant neoplasia. However, genomic profiling of papillary thyroid cancer (PTC) cases from Taiwan has not been attempted previously. We used whole-exome sequencing to identify mutations in a cohort of 19 PTC patients. Sequencing was performed using the Illumina system; Sanger sequencing was used to validate all identified mutations. We identified new somatic mutations in APC, DICER1, LRRC8D and NDRG1. We also found somatic mutations in ARID5A, CREB3L2, MDM4, PPP2R5A and TFPT; mutations in these genes had been found previously in other tumors, but had not been described previously in PTC. We also investigated the pathway deregulation in BRAF-mutated PTC compared with wild-type BRAF PTC. In checking our gene mutations against The Cancer Genome Atlas (TCGA) database, we identified aberrations in one pathway that are specific to BRAF-mutated PTC: maturity-onset diabetes of the young. In addition, the caffeine metabolism pathway showed aberrations that are specific to wild-type BRAF PTC. For this study, we performed a comprehensive exome-wide analysis of the mutational spectra of Taiwanese patients with PTC. We identified novel genes that are potentially associated with PTC tumorigenesis, as well as aberrations in pathways that led to the distinct pathogeneses of BRAF-mutated PTC and wild-type BRAF PTC, which may provide a new target for PTC therapy.

Detection of Molecular Alterations in Taiwanese Patients with Medullary Thyroid Cancer Using Whole-Exome Sequencing

Genetic and epigenetic alterations are associated with the progression and prognosis of medullary thyroid carcinoma (MTC). We performed whole-exome sequencing of tumor tissue from seven patients with sporadic MTC using an Illumina HiSeq 2000 sequencing system. We conducted Sanger sequencing to confirm the somatic mutations in both tumor and matched normal tissues. We applied Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis with the Database for Annotation, Visualization, and Integrated Discovery and STRING for pathway analysis. We detected new somatic mutations in the BICD2, DLG1, FSD2, IL17RD, KLHL25, PAPPA2, PRDM2, PSEN1, SCRN1, and TTC1 genes. We found a somatic mutation in the PDE4DIP gene that had previously been discovered mutated in other tumors but that had not been characterized in MTC. We investigated pathway deregulation in MTC. Data regarding 1152 MTCs were assembled from the Catalogue of Somatic Mutations in Cancer (COSMIC) and seven of our patients. Ontological analysis revealed that most of the variants aggregated in pathways that included the signaling pathways of thyroid cancer, central carbon metabolism, microRNAs in cancer, PI3K-Akt, ErbB, MAPK, mTOR, VEGF, and RAS. In conclusion, we conducted wide-ranging exome-wide analysis of the mutational spectrum of MTC in Taiwan’s population and detected novel genes with potential associations with MTC tumorigenesis and irregularities in pathways that resulted in MTC pathogenesis.

Whole-exome sequencing for the genetic diagnosis of congenital red blood cell membrane disorders in Taiwan

PURPOSE Congenital hemolytic anemia caused by red blood cell (RBC) membrane defects is a heterogeneous group of disorders. The present study aimed to search the causative gene mutations in patients with RBC membrane disorders in Taiwan. MATERIALS AND METHODS Next-generation sequencing approach using whole-exome sequencing (WES) was performed. Sanger sequencing was performed for confirmation of variants detected in WES in patients and their family members. RESULTS Five causative variants, including two ANK1, two SPTA and one SPTB variants, were detected in four patients. All these variants, except one SPTA1 variant c.83G > A (p.R28H), are novel variants. Their pedigree analysis showed one de novo SPTA1 mutation c.83G > A (p.R28H) combined with αLELY, one de novo ANK1 mutation c.1034C > A (p.A345E), one autosomal dominant combined SPTA1 c.4604A > C (p.Q1535P) and SPTB c.6203 T > C (p.L2068P) mutations and one autosomal dominant ANK1 c.4462C > T (p.R1488X) mutation. CONCLUSIONS Our data demonstrated that WES is an efficient tool for determining genetic etiologies of RBC membrane disorders and can facilitate accurate diagnosis and genetic counseling. Additional studies should be conducted on larger cohorts to investigate the distribution of gene mutations in patients with RBC membrane disorders in Taiwan.

Next-generation sequencing profiling of mitochondrial genomes in gout

BackgroundAccumulating evidence implicates mitochondrial DNA (mtDNA) alleles, which are independent of the nuclear genome, in disease, especially in human metabolic diseases. However, this area of investigation has lagged behind in researching the nuclear alleles in complex traits, for example, in gout.MethodsNext-generation sequencing was utilized to investigate the relationship between mtDNA alleles and phenotypic variations in 52 male patients with gout and 104 age-matched male non-gout controls from the Taiwan Biobank whole-genome sequencing samples. Differences from a reference sequence (GRCh38) were identified. The sequence kernel association test (SKAT) was applied to identify gout-associated alleles in mitochondrial genes. The tools Polymorphism Phenotyping, Sorting Intolerant From Tolerant (SIFT), Predict the pathology of Mutations (PMUT), Human Mitochondrial Genome Database (mtDB), Multiple Alignment using Fast Fourier Transform (MAFFT), and Mammalian Mitochondrial tRNA Genes (Mamit-tRNA) were used to evaluate pathogenicity of alleles. Validation of selected alleles by quantitative polymerase chain reaction of single nucleotide polymorphisms (qPCR SNPs) was also performed.ResultsWe identified 456 alleles in patients with gout and 640 alleles in non-gout controls with 274 alleles shared by both. Mitochondrial genes were associated with gout, with MT-CO3, MT-TA, MT-TC, and MT-TT containing potentially pathogenic gout-associated alleles and displaying evidence of gene-gene interactions. All heteroplasmy levels of potentially pathogenic alleles exceeded metabolic thresholds for pathogenicity. Validation assays confirmed the next-generation sequencing results of selected alleles. Among them, potentially pathogenic MT-CO3 alleles correlated with high-density lipoprotein (HDL) levels (P = 0.034).ConclusionThis study provided two scientific insights. First, this was the most extensive mitochondrial genomic profiling associated with gout. Second, our results supported the roles of mitochondria in gout and HDL, and this comprehensive analysis framework can be applied to other diseases in which mitochondrial dysfunction has been implicated.