RNAi-mediated downregulation of DNA binding protein A inhibits tumorigenesis in colorectal cancer

Abstract

DNA binding protein A (dbpA) belongs to the Y-box binding protein family and has been reported to play an important role in carcinogenesis. Our previous study demonstrated that the knockdown of dbpA in gastric cancer cells inhibited cell proliferation by modulating the cell cycle. However, the role of dbpA in human colorectal cancer (CRC) remains unclear. In this study, immunohistochemical (IHC) staining and clinicopathological parameter analysis were employed to detect dbpA expression in 44 paired CRC samples and 7 CRC cell lines. Lentivirus-mediated short hairpin RNA (shRNA) was used to silence dbpA, and the effects of dbpA knockdown on cell proliferation were determined by MTT assay, colony formation assay and flow cytometry. Furthermore, a xenograft model was established to observe tumor growth in vivo. Functional analysis indicated that dbpA was overexpressed in the CRC tissues and cell lines, and a high dbpA expression was associated with the depth of invasion (p<0.001), the degree of differentiation (p<0.001), lymphatic metastasis (p<0.001) and vessel invasion (p<0.001). The suppression of dbpA expression resulted in decreased cell proliferation in vitro and tumor growth in vivo, and it induced cell cycle arrest and promoted the apoptosis of the CRC cells. As a whole, our findings illustrate the crucial role of dbpA in colorectal tumorigenesis. Thus, dbpA may be used as a novel and potent therapeutic target in CRC.

Gene expression profile analysis of dbpA knockdown in colorectal cancer cells

“…CDC42 overexpression could result in the initiation of oncogenic condition, since previous studies have verified that CDC42 activation was associated with invasive metastasis, cell division, and progress in various cancers, such as melanoma, colorectal, and breast cancer (Arias-Romero and Chernoff, 2013; Ye et al, 2015). Our recent study has demonstrated that CRC development was inhibited with dbpA knockdown (Liu et al, 2016), thus, we speculate that the down-regulation of CDC42 in CRC cells with dbpA silencing is more convincing and reasonable. To validate our hypothesis, further investigation is still needed to reveal the relationship between dbpA knockdown and CDC42 activity in CRC development.…”

“…Our previous study showed that dbpA overexpression was associated with the tumorigenesis of CRC (Liu et al, ). In this study, network analysis and Western blot results showed that silencing of dbpA caused the decreased activation of TAK1, p38MAPK, and JNK1/2 in CRC cell lines in a time‐dependent manner, which indirectly demonstrated that dbpA might aggravate the development of CRC by stimulating MAPK signaling pathway.…”

“…It is an urgent to have a better understanding of the genetic changes that lead to the development of CRC. Our recent study has demonstrated that dbpA is significantly over‐expressed in CRC tissue samples and SW620 cell line (Liu et al, ), which is associated with the proliferation and development of CRC cells.…”

Knockdown of DNA‐binding protein A enhances the chemotherapy sensitivity of colorectal cancer via suppressing the Wnt/β‐catenin/Chk1 pathway

“…A quantitative reverse transcription polymerase chain reaction was performed as previously reported (R.‐T. Liu et al, 2016). The primer sequences are shown in Table S1.…”

“…Downregulation of dbpA inhibited cell proliferation, induced cell apoptosis, and cycle arrest in CRC cells (R.‐T. Liu et al, 2016). However, it remains unclear whether there is a role of dbpA in mediating 5‐FU‐sensitivity in CRC cells.…”