How do the effective therapeutics for hepatocellular carcinoma treatment change PIWI Interacting RNA expressions

Aim: PIWI interacting RNAs (piRNAs) are novel members of small non-coding RNAs that cannot produce proteins but are effective on transcription and post-transcriptional mechanisms of cells. Nowadays, the application of both natural compounds and vitamins is essential for treatment of cancer cells instead of chemical compounds. In this study, we aimed to detect possible expression changes of piRNAs in order to compare 4- Hydroxycoumarin to the active form of vitamin D (1.25-Dihydroxyvitamin D) in hepatocellular carcinoma. Methods: According to our previous study, HePG2 cells were treated with 4- Hydroxycoumarin, 1.25-Dihydroxyvitamin D and drug form of vitamin D at the optimal time and concentration. After treatment, the total RNA was isolated and expressions of piR-Hep-1 and piR-651 were determined by using Real Time Polymerase Chain Reactions. Results: According to our obtained data, statistically significant upregulation of piR-651 expression was observed in 4-Hydroxycoumarin-treated HePG2 cells compared to control (p<0.001). However, the expression of piR-Hep-1 statistically was not affected from 4- Hydroxycoumarin treatment (p>0.05). In contrast, 1.25-dihydroxyvitamin treatment downregulated the expression of piR-Hep-1 statistically significant in HePG2 cells (p<0.001). piR-Hep-1 was not statistically significant effected from drug form of vitamin D treatment (p>0.05). Conlusion: Our results indicated that some of the piRNAs might have special expression patterns in hepatocellular carcinoma and these expression patterns can be regulated by treated natural compounds. We suggest that substances that are observed to be effective in hepatocellular carcinoma individually may result in different piRNA expression changes contrary to the expectations.