Prognostic Significance of FKBP14 in Gastric Cancer

Abstract

Introduction: Although our understanding on gastric cancer biology is better than a decade ago, its practical effect on screening and diagnosis remains limited. Moreover, there are no markers that can be accurately used in the clinic to diagnose early-stage gastric cancer or monitor the patient's response to therapy. Herein, we investigate whether FKBP14 is involved in the progression of gastric cancer.

Methods: The AGS cell line was chosen for over-expression analysis, whereas the SGC-7901 cell line was selected for knock-down analysis. AGS cells were transfected with an FKBP14 overexpression plasmid (AGS-PLV.O-FLAG). The expression pattern of FKBP14 in both cell lines was determined by Western blot and RT-PCR. Cell proliferation was assessed using Cell Counting Kit-8, whereas apoptosis was performed using flow cytometry. The expression of FKBP14 in 70 Chinese patients with gastric cancer was also investigated using tissue microarrays and compared with gastric cancer patients from The Cancer Genome Atlas.

Results: FKBP14 was highly expressed in SGC7901 and had a relatively low expression in AGS cells. Upregulation of FKBP14 in AGS cells promoted migration and invasion and inhibits apoptosis. Knock-down of FKBP14 resulted in a suppression in migration and invasion and promoted apoptosis in the SGC-7901 cell line. Effectively, gastric cancer patients had a higher expression of FKBP14, with a lower survival rate (P = 0.028). Patients with a high expression of FKBP14 were significantly correlated with lymph node metastasis (P =0.016), and an advanced histologic grade (P =0.021).

Conclusion: FKBP14 is often up-regulated in gastric cancer. Patients with a high expression of FKBP14 are usually associated with worse overall survival. FKBP14 is an oncogene in gastric cancer, and is a potential biomarker for GC diagnosis, invasion, and prognosis.

Keywords: FKBP14; The Cancer Genome Atlas; gastric cancer; in vitro; prognosis.

Figure 1

(A): The relative expression of FKBP14 was investigated in several cell lines; **P < 0.05, *** P < 0.001. We selected the AGS cell line for over-expression analysis and the SGC-7901 for knock-down analysis. (B):1) Using AGS-NC-FLAG as a control, we observe that AGS-FKBP14-FLAG has a very significant overexpression effect (>100%); (C1, C2): qPCR confirmed the over-expression of FKBP14 in the plasmid (D, E): Western blot further confirmed the over-expression of FKBP14 in the plasmid; ***P < 0.01.

Figure 2

(A) At 4hrs, there was no significant difference in OD values between the two groups, P>0.05. Statistical significance was observed at 24hrs and 48hrs; the OD value of AGS-PLV.O-FLAG-FKBP14 in the experimental group was higher than that in the control group; * P<0.05. Further statistical significance was observed at 72hrs, whereby the OD value of the experimental group AGS-PLV.O-FLAG-FKBP14 was higher than that of the control group AGS-PLV.O-FLAG; **P<0.001. (B) Compared with the control group, the invasive rate of AGS cells was significantly increased after overexpression of FKBP14; **P < 0.001. (C) At 6hrs, compared with the control group, the experimental group AGS-PLV.O-FLAG-FKBP14 had a higher mobility rate; *P<0.05. At 24 h, there was no significant difference between the two groups. (D) There was a significant decrease in the rate of apoptosis for the AGS cell line after over-expression with FKBP14; *P < 0.05.

Figure 3

(A): A significant knock-down effect was observed in the SGC7901-si-FKBP14-002 and the SGC7901-si-FKBP14-003 cell line. (B): Compared with the control group (SGC7901-si-FKBP14-NC), the mRNA expression level of FKBP14 in the inhibition group (SGC7901-si-FKBP14-001, SGC7901-si-FKBP14-002, SGC7901-si-FKBP14-003) was significantly decreased; **P<0.05. (C): At 24hrs and 48hrs, respectively, the mobility of the experimental group SGC7901-si-FKBP14-002 was lower than that of the control group; **P<0.01. (D): Apoptosis in the SGC7901 cell line was increased after inhibition of FKBP14; *P<0.05.

Figure 4

(A): The tissue micro-array (B): An overexpression of FKBP14 protein was significantly associated with lymph node metastasis; *P < 0.05, and neoplasm histologic Grade; *P < 0.05. (C–F): FKBP14 immunostainings occur more strongly in the cytoplasm of gastric cancer tissues.

Figure 5

The Kaplan-Meier survival curve from the 70 gastric cancer patients used in this study shows a high expression of FKBP14 expression is significantly correlated to poor survival (P < 0.05).