Knockdown of tankyrase 1 inhibits the progression of gastric adenocarcinoma via regulating human telomerase reverse transcriptase and telomeric repeat binding factor 1

Abstract

Background: Gastric cancer is one of the most lethal cancers. Aberrant expression levels of genes are frequently associated with cell immortalization and the occurrence of tumors. In this study, we aimed to investigate the role of tankyrase 1 (TANK1) in gastric adenocarcinoma and clarify the underlying mechanism.

Methods: The messenger RNA (mRNA) levels of TANK1, human telomerase reverse transcriptase (h-TERT), and telomeric repeat binding factor 1 (TRF1) in clinical specimens and SGC-7901 cells were measured via real-time quantitative polymerase chain reaction (RT-qPCR). Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and immunohistochemistry (IHC) assays were utilized to observe the cell apoptosis as well as Ki67 and h-TERT expression in tumor-bearing models. The effects of TANK1 antisense oligonucleotides (TANK1 ASODN) on viability and apoptosis of SGC 7901 cells were evaluated by cell counting kit-8 and flow cytometry analysis.

Results: We found that TANK1 and h-TERT were both increased in gastric adenocarcinoma, while TRF1 was decreased. Tumor-bearing models demonstrated that TANK1 ASODN appeared to be effective in inhibiting tumor growth and decreasing the expression of h-TERT. Additionally, TANK1 ASODN inhibited the viability and promoted apoptosis of SGC-7901 cells. Moreover, the mRNA levels of h-TERT and TRF1 were modulated by TANK1 ASODN.

Conclusions: This study revealed that TANK1 ASODN inhibits the proliferation and induced the apoptosis of gastric adenocarcinoma cells via manipulating the expression levels of h-TERT and TRF1.

Keywords: Tankyrase 1 (TANK1); gastric adenocarcinoma; human telomerase reverse transcriptase (h-TERT); telomeric repeat binding factor 1 (TRF1).

Figure 1

The expression levels of TANK1, h-TERT, and TRF1 in gastric adenocarcinoma and adjacent non-tumor tissues. (A) The mRNA levels of TANK1 in clinical specimens; (B) the mRNA levels of h-TERT in clinical specimens; (C) the mRNA levels of TRF1 in clinical specimens. Data are represented as mean ± standard deviation, ***P<0.001. mRNA, messenger RNA.

Figure 2

TANK1 ASODN delays tumor growth and promotes cell apoptosis in SGC-7901 tumor-bearing mice. (A) The photos of tumor tissues and the growth curves of SGC-7901 tumor volume growth in each group; (B) TUNEL assay was used to stain the apoptotic cells in tumor tissues. Magnification, ×100. Data are represented as mean ± standard deviation, **P<0.01, ***P<0.001 vs. the vehicle group. TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling.

Figure 3

TANK1 ASODN delays tumor growth and increases cell apoptosis in in SGC-7901 tumor-bearing mice. (A) The distribution of Ki67 was stained by IHC assay; (B) IHC assay was used for measurement of h-TERT expression. Magnification, ×100. Data is represented as mean ± standard deviation, *P<0.05, **P<0.01 vs. the vehicle group; ^#P<0.05 vs. the TANK1 SODN group. IHC, immunohistochemistry.

Figure 4

Silencing TANK1 inhibits the proliferation and promotes the apoptosis of gastric adenocarcinoma cells. (A) RT-qPCR was conducted to investigate the mRNA levels of TANK1; (B) cell viability was measured by CCK-8 assay; (C,D) flow cytometry analysis was utilized to examine apoptotic cells. Data are represented as mean ± standard deviation, **P<0.01, ***P<0.001 vs. the vehicle group; ^#P<0.05, ^##P<0.01, ^###P<0.001 vs. the Control group. RT-qPCR, reverse transcription quantitative polymerase chain reaction; mRNA, messenger RNA; CCK-8, cell counting Kit-8.

Figure 5

Knockdown of TANK1 affects the expression levels of h-TERT and TRF1. (A) The relative expression of h-TERT was evaluated by RT-qPCR; (B) RT-qPCR was performed to estimate the mRNA levels of TRF1. Data was represented as mean ± standard deviation, **P<0.01 vs. the vehicle group. RT-qPCR, reverse transcription quantitative polymerase chain reaction; mRNA, messenger RNA.