Lung carcinoma is the most common human cancer with poor prognosis and has an increasing incidence in recent years. However, the related mechanism of lung cancer onset has not been completely explored. Piwi-interacting RNA (piRNA) is a type of noncoding small RNA with established function in germ cells, and interestingly, piRNA has also been shown to be implicated in cancer biology. In this study, piR-55490 was found to be silenced in lung carcinoma specimens and cell lines, compared with normal lung tissues and cells. Intriguingly, the expression level of piR-55490 is negatively associated with patients' survival. Restoration of piR-55490 can reduce the proliferation rates of lung cancer cells, while piR-55490 suppression led to the gain in the proliferation rates. Animal model study showed that piR-55490 can suppress the growth of lung carcinoma xenograft. Further study revealed that piR-55490 suppressed the activation of Akt/mTOR pathway in lung cancer cells. Surprisingly, piR-55490 was found to bind 3'UTR of mTOR messenger RNA (mRNA) and induce its degradation in a mechanism similar to microRNA (miRNA). The introduction of an mTOR construct resistant to action of piR-55490 was able to abolish the effect of piR-55490 on lung cancer cells. In conclusions, we found that piRNA can contribute to the suppression of cancer cell phenotypes by directly targeting a oncogene mRNA. This finding facilitates our understanding of piRNA's function and its association with human cancer.
Zinner syndrome (ZS) is a rare anomaly of the Wolffian duct. We searched for case reports and case series to identify the most effective methods for examination and treatment. The PubMed/Medline, Embase, and Scopus databases were searched. Our searches yielded 160 case reports/case series and included 214 patients. The mean age at diagnosis was 29.35 years. The R:L distribution was 1:1. The most common symptoms were: frequency (24.3%), dysuria (23.1%) and perineal pain (20.2%) in ZS patients with clinical symptoms. The diagnostic investigations used most frequently were magnetic resonance imaging (MRI) (67.8%) and ultrasonography (65.0%). Maximum flow rate on uroflowmetry, semen ejaculate volume, sperm count, and sperm motility were significantly lower in patients with ZS. Among 193 patients with treatment details, 65.8% underwent surgery; 9.8% underwent aspiration; 24.3% were followed with observation.Two patients died after surgery; all other patients remained asymptomatic after surgery. Fifty-two patients had complications and comorbidities. In patients with ZS, the most common symptoms are seminal vesicle cyst enlargement and compression of the bladder, ureter, and reproductive system. The diagnosis mostly depends on radiological examination. Surgery may be effective, but complications may occur.
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