Knockdown of TACC3 Inhibits the Proliferation and Invasion of Human Renal Cell Carcinoma Cells

Abstract

Transforming acidic coiled-coil protein 3 (TACC3) is a member of the TACC family and plays an important role in regulating cell mitosis, transcription, and tumorigenesis. However, the expression pattern and roles of TACC3 in renal cell carcinoma (RCC) remain unclear. The aim of this study was to investigate the role of TACC3 in RCC. We demonstrated overexpression of TACC3 in human RCC cell lines at both RNA and protein levels. Moreover, knockdown of TACC3 repressed RCC cell proliferation, migration, and invasion in vitro. In addition, knockdown of TACC3 inactivated PI3K/Akt signaling in RCC cells. Furthermore, knockdown of TACC3 significantly reduced tumor growth in xenograft tumor-bearing mice. Taken together, our findings showed that TACC3 was increased in human RCC cell lines, and knockdown of TACC3 inhibited the ability of cell proliferation, migration, invasion, and tumorigenesis in vivo. Therefore, TACC3 may act as a therapeutic target for the treatment of human RCC.

Figure 1

Upregulation of TACC3 expression in human renal cell carcinoma (RCC) cell lines. (A) The mRNA expression of transforming acidic coiled-coil protein 3 (TACC3) in human RCC cell lines was evaluated by quantitative real-time (qRT)-PCR. (B) Protein expression of TACC3 in human RCC cell lines was evaluated by Western blot. *p < 0.05 versus HK-2 group.

Figure 2

Effects of TACC3 downregulation on RCC cell proliferation. Caki-1 cells were transfected with shRNA-TACC3 or shRNA-Scr for 24 h, respectively. (A) The mRNA expression of TACC3 in Caki-1 cells was evaluated by qRT-PCR. (B) Protein expression of TACC3 in Caki-1 cells was evaluated by Western blot. (C) The effect of TACC3 on cellular proliferation in Caki-1 cells was measured using the MTT assay. *p < 0.05 versus shRNA-Scr group.

Figure 3

Effects of TACC3 downregulation on RCC cell migration and invasion. Caki-1 cells were transfected with shRNA-TACC3 or shRNA-Scr for 24 h, respectively. (A) The effect of TACC3 on cellular migration in Caki-1 cells was detected using the Transwell migration assay. (B) The effect of TACC3 on cellular invasion in Caki-1 cells was evaluated using the Matrigel invasion assay. (C) The protein expression levels of E-cadherin and vimentin were detected by Western blot. *p < 0.05 versus shRNA-Scr group.

Figure 4

Silencing TACC3 inhibits the PI3K/Akt signaling pathway in RCC cells. Caki-1 cells were transfected with short hairpin RNA (shRNA)-TACC3 or shRNA-Scr for 24 h, respectively. (A) Protein expression levels of p-PI3K and p-Akt were detected by Western blot. (B) Quantification analysis was performed using Gel-Pro Analyzer version 4.0 software. (C, D) Caki-1 cells were infected with shRNA-TACC3 or shRNA-Scr, and migration and invasion assays were performed in the presence of either DMSO or Akt inhibitor (MK-2206, 10 μM). *p < 0.05 versus shRNA-Scr group, #p < 0.05 versus shRNA-TACC3 group, &p < 0.05 versus MK-2206 group.

Figure 5

The effect of TACC3 expression on in vivo Caki-1 tumorigenicity. Infected 1 × 10⁶ Caki-1 cells were injected subcutaneously into the flanks of nude mice (n = 10/group). (A) Tumor volume was measured using calipers. (B) Three weeks after injection, mice were sacrificed, and the tumors were removed and weighed. *p < 0.05 versus shRNA-Scr group.