SiRNF8 Delivered by DNA Framework Nucleic Acid Effectively Sensitizes Chemotherapy in Colon Cancer

Abstract

Background

The evident side effects and decreased drug sensitivity significantly restrict the use of chemotherapy. However, nanoparticles based on biomaterials are anticipated to address this challenge.

Methods

Through bioinformatics analysis and colon cancer samples, we initially investigated the expression level of RNF8 in colon cancer. Next, we constructed nanocarrier for delivering siRNF8 based on DNA tetrahedron (si-Tet), and Doxorubicin (DOX) was further intercalated into the DNA structure (si-DOX-Tet) for combination therapy. Further, the effects and mechanism of RNF8 inhibition on the sensitivity of colon cancer cells to DOX chemotherapy have also been studied.

Results

RNF8 expression was increased in colon cancer. Agarose gel electrophoresis, transmission electron microscopy, and size distribution and potential analysis confirmed the successful preparation of the two nanoparticles, with particle sizes of 10.29 and 37.29 nm, respectively. Fluorescence imaging reveals that the carriers can be internalized into colon cancer cells and escape from lysosomes after 12 hours of treatment, effectively delivering siRNF8 and DOX. Importantly, Western blot analysis verified treatment with 50nM si-Tet silenced RNF8 expression by approximately 50% in colon cancer cells, and combined treatment significantly inhibited cell proliferation. Furthermore, the CCK-8 assay demonstrated that si-Tet treatment enhanced the sensitivity of colon cancer cells to the three chemotherapeutic drugs. Significant more DNA damage was detected after treatment with both si-Tet or si-DOX-Tet. Further flow cytometry analysis revealed that si-DOX-Tet treatment led to significantly more apoptosis, approximately 1.6-fold higher than treatment with DOX alone. Mechanistically, inhibiting RNF8 led to decreased ABCG2 expression and DOX efflux, but increased DNA damage, thereby enhancing the chemotherapeutic effect of DOX.

Conclusion

We have successfully constructed si-DOX-Tet. By inhibiting the expression of RNF8, it enhances the chemotherapy sensitivity of DOX. Therefore, this tetrahedral FNA nanocarrier offers a new approach for the combined treatment of colon cancer.

Graphical Abstract

Keywords:

• DNA framework nucleic acid
• RNF8
• chemosensitivity
• RNAi
• colorectal cancer

Abbreviations

CRC, Colorectal cancer; DOX, Doxorubicin; EMT, epithelial-mesenchymal transition; Tet, tetrahedron; TEM, Transmission electron microscope; FNA, Frame nucleic acid, DSBs, Double-strand breaks; ABC, ATP binding cassette.

Data Sharing Statement

All relevant data are included in the main manuscript and supplementary materials. Supporting/raw data are available from the corresponding author on reasonable request.

Disclosure

The authors declare no conflict of interest.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (Grants No. 82071695 to Degui Wang and No. 82060535 to Yingxia Tian) and lzuyxcx-2022-155 from Medical Innovation and Development Project of Lanzhou University.