26523

AGO1

argonaute RISC catalytic component 1;AGO1;argonaute RISC catalytic component 1

Golgi Endoplasmic Reticulum protein 95 kDa|argonaute 1|argonaute1|eIF-2C 1|eIF2C 1|eukaryotic translation initiation factor 2C, 1|hAgo1|protein argonaute-1|putative RNA-binding protein Q99

1p34.3

protein-coding

Based on the important role of microRNA (miRNA) biosynthesis genes in carcinogenesis, we hypothesized that polymorphisms in the miRNA biosynthesis genes may modulate susceptibility to lung cancer. To test this hypothesis, we conducted a two-stage study to evaluate the associations between single nucleotide polymorphisms (SNPs) in the miRNA biosynthesis genes and the risk of lung cancer. In stage 1 of the study, 24 SNPs in the 11 miRNA biosynthesis genes (DROSHA, DGCR8, RAN, XPO5, DICER, AGO1, AGO2, HIWI, GEMIN3, GEMIN4, and TRBP) were genotyped in 100 lung cancer patients and 100 healthy controls using a sequenome mass spectrometry-based genotyping assay. One promising SNP (AGO1 rs636832A > G) was selected for stage 2 of the study, and genotyped by a melting-curve analysis using fluorescence-labeled hybridization probes in an independent set of 552 cases and 552 controls. The AGO1 rs636832A > G exhibited highly consistent results between the two stages of the study. In combined analysis, the 636832A > G was associated with a significantly decreased risk of lung cancer in a dose-dependent manner (P(trend) = 6.0 x 10(-4)). Individuals with at least one rs636832G allele were at a significantly decreased risk of lung cancer compared with those with the AA genotype (adjusted odds ratio = 0.67, 95% confidence interval = 0.53-0.84, P = 4.0 x 10(-4)). This finding suggests that the AGO1 rs636832A > G might be a useful marker for determining the susceptibility to lung cancer and that the AGO1 gene might be involved in the development of lung cancer.

MicroRNAs are posttranscriptional regulators of messenger RNA synthesis that are intracellularly processed and transferred by the microRNA-regulating machinery consisting of Drosha, Dicer, and Argonaute. The present study analyzed the expression and clinical role of the microRNA-regulating machinery in advanced-stage ovarian carcinoma. Drosha, Dicer, Argonaute 1, and Argonaute 2 messenger RNA levels were analyzed in 144 specimens (82 effusions, 33 primary carcinomas, and 29 solid metastases) using quantitative polymerase chain reaction. Dicer, Argonaute 1, and Argonaute 2 protein levels were analyzed in 103 of the above specimens by Western blotting. Argonaute 1, Argonaute 2, and Drosha messenger RNAs were overexpressed in effusions compared with primary carcinomas and solid metastases (P<.001), whereas Argonaute 1 protein expression was highest in solid metastases (P=.004). Significantly higher expression of all 4 messenger RNAs was found in effusions compared with primary carcinomas (P<.001 to P=.006), whereas Argonaute 2 messenger RNA (P=.002), Drosha messenger RNA (P=.009), and Dicer protein (P=.006) were overexpressed in solid metastases compared with primary carcinomas. Drosha, Dicer, Argonaute 1, and Argonaute 2 messenger RNAs and protein levels in effusions were unrelated to clinicopathologic parameters. In primary carcinomas, higher levels of 3 messenger RNAs were significantly associated with high-grade histology (P=.003 for Dicer and P=.01 for Drosha and Argonaute 1). Higher Argonaute 2 messenger RNA levels in prechemotherapy effusions were related to shorter progression-free survival (P=.049), a finding that retained its significance in multivariate Cox analysis (P=.046). In conclusion, Drosha, Dicer, Argonaute 1, and Argonaute 2 are differentially expressed at different metastatic sites in ovarian carcinoma compared with primary carcinomas, suggesting a role for these molecules in tumor progression. Their clinical role in metastatic ovarian carcinoma merits further research.