Identification of Genes Responding to Low-Dose Arsenite Using HiCEP

Interaction of Arsenic Exposure and Transcriptomic Profile in Basal Cell Carcinoma

Exposure to inorganic arsenic (As) is recognized as risk factor for basal cell carcinoma (BCC). We have followed-up 7000 adults for 6 years who were exposed to As and had manifest As skin toxicity. Of them, 1.7% developed BCC (males = 2.2%, females = 1.3%). In this study, we compared transcriptome-wide RNA sequencing data from the very first 26 BCC cases and healthy skin tissue from independent 16 individuals. Genes in “ cell carcinoma pathway”, “Hedgehog signaling pathway”, and “Notch signaling pathway” were overexpressed in BCC, confirming the findings from earlier studies in BCC in other populations known to be exposed to As. However, we found that the overexpression of these known pathways was less pronounced in patients with high As exposure (urinary As creatinine ratio (UACR) > 192 µg/gm creatinine) than patients with low UACR. We also found that high UACR was associated with impaired DNA replication pathway, cellular response to different DNA damage repair mechanisms, and immune response. Transcriptomic data were not strongly suggestive of great potential for immune checkpoint inhibitors; however, it suggested lower chance of platinum drug resistance in BCC patients with high UACR compared high platinum drug resistance potential in patients with lower UACR.

Genome-wide gene expression profiling in gamma-irradiated green alga, Pseudokirchneriella subcapitata, by HiCEP

Transcriptome was analyzed in gamma-irradiated green alga Pseudokirchneriella subcapitata by high coverage gene expression profiling (HiCEP). Approximately 7,800 expressed genes were detected. Expression levels of 623-707 genes were affected at 100-300 Gy. Nucleotide sequences of 41 up-regulated genes were determined. The quantitative reverse transcription polymerase chain reaction validated the up-regulation. Two genes had homology to genes related to ionizing radiation. These results indicate usefulness of HiCEP for screening of stress-responsive genes in species that are ecotoxicologically important but for which genomic sequence information is lacking.