Obstet Gynecol Sci.  2015 May;58(3):210-216. 10.5468/ogs.2015.58.3.210.

Long (27-nucleotides) small inhibitory RNAs targeting E6 protein eradicate effectively the cervical cancer cells harboring human papilloma virus

• Cho JS
• Lee SW
• Kim YM
• Kim D
• Kim DY
• Kim YT

• KMID: 2148933
• DOI: http://doi.org/10.5468/ogs.2015.58.3.210

Abstract

OBJECTIVE
This study was to identify small inhibitory RNAs (siRNAs) that are effective in inhibiting growth of cervical cancer cell lines harboring human papilloma virus (HPV) and to examine how siRNAs interact with interferon beta (IFN-beta) and thimerosal.
METHODS
The HPV18-positive HeLa and C-4I cell lines were used. Four types of siRNAs were designed according to their target (both E6 and E7 vs. E6 only) and sizes (21- vs. 27-nucleotides); Ex-18E6/21, Ex-18E6/27, Sp-18E6/21, and Sp-18E6/27. Each siRNA-transfected cells were cultured with or without IFN-b and thimerosal and their viability was measured.
RESULTS
The viabilities of HPV18-positive tumor cells were reduced by 21- and 27-nucleotide siRNAs in proportion to the siRNA concentrations. Of the two types of siRNAs, the 27-nucleotide siRNA constructs showed greater inhibitory efficacy. Sp-18E6 siRNAs, which selectively downregulates E6 protein only, were more effective than the E6- and E7-targeting Ex-18E6 siRNAs. siRNAs and IFN-beta showed the synergistic effect to inhibit HeLa cell survival and the effect was proportional to both siRNA and IFN-beta concentrations. Thimerosal in the presence of siRNA exerted a dose-dependent inhibition of C-4I cell survival. Finally, co-treatment with siRNA, IFN-beta, and thimerosal induced the most profound decrease in the viability of both cell lines.
CONCLUSION
Long (27-nucleotides) siRNAs targeting E6-E7 mRNAs effectively reduce the viability of HPV18-positive cervical cancer cells and show the synergistic effect in combination with IFN-b and thimerosal. It is necessary to find the rational design of siRNAs and effective co-factors to eradicate particular cervical cancer.

Keyword

E6 protein; E7 protein; Human papilloma virus type 18; Small inhibitory RNA; Uterine cervical neoplasms

MeSH Terms

Cell Line
Cell Survival
HeLa Cells
Humans
Interferon-beta
Papilloma*
RNA*
RNA, Messenger
RNA, Small Interfering
Thimerosal
Uterine Cervical Neoplasms*
Interferon-beta
RNA
RNA, Messenger
RNA, Small Interfering
Thimerosal