High expression of glucose-regulated protein 78 (GRP78) is associated with metastasis and poor prognosis in patients with esophageal squamous cell carcinoma

Figures & data

Figure 1 The expression of GRP78 protein in ESCC tissues and cell lines was assessed through Western blot.

Notes: (A) Western blot results of GRP78 protein levels in ESCC tissues and adjacent normal esophageal mucosal tissues. The GRP78 protein levels are higher in ESCC tissues (T) than in adjacent normal esophageal mucosal tissues (N) from the same patient. (B) Western blot results of GRP78 protein levels in different ESCC cell lines. The GRP78 protein levels are high in the three ESCC cell lines.
Abbreviations: ESCC, esophageal squamous cell carcinoma; GRP78, glucose-regulated protein 78.

Figure 2 Expression of GRP78 was detected by immunohistochemistry.

Notes: (A) Negative staining of GRP78 in normal esophageal epithelium (400×). (B) High expression of GRP78 in normal esophageal epithelium (400×). (C) Low expression of GRP78 in ESCC tissues (400×). (D) High expression of GRP78 in ESCC tissues (400×).
Abbreviations: ESCC, esophageal squamous cell carcinoma; GRP78, glucose-regulated protein 78.

Figure 3 Association between the GRP78 expression levels and OS of ESCC patients.

Note: The 5-year survival rates of esophageal cancer patients with low GRP78 expression levels were significantly higher than those with high GRP78 expression levels (P=0.037).
Abbreviations: ESCC, esophageal squamous cell carcinoma; GRP78, glucose-regulated protein 78; OS, overall survival.

Table 1 Correlation between the expression of GRP78 protein and clinicopathological features

Clinicopathological features	Case	GRP78 expression		χ^2	P-value
		Low (%)	High (%)
Total number of patients	92	26 (28.3)	66 (71.7)
Gender				0.237	0.627
Male	67	18 (26.9)	49 (73.1)
Female	25	8 (32.0)	17 (68.0)
Age (years)				1.930	0.165
<65	46	16 (34.8)	30 (65.2)
≥65	46	10 (21.7)	36 (78.3)
Smoking status				0.106	0.745
None	33	10 (30.3)	23 (69.7)
Yes	59	16 (27.1)	43 (72.9)
Alcohol consumption status				0.531	0.466
None	37	12 (32.4)	25 (67.6)
Yes	55	14 (25.5)	41 (74.5)
Tumor location				1.582	0.453
Upper	2	1 (50)	1 (50)
Middle	73	22 (30.1)	51 (69.9)
Lower	17	3 (17.6)	14 (82.4)
Histological grade				3.314	0.191
G1	10	1 (10)	9 (90)
G2	65	18 (27.7)	47 (72.3)
G3	17	7 (41.2)	10 (58.8)
Tumor size (cm)				1.930	0.165
<4	46	16 (34.8)	30 (65.2)
≥4	46	10 (21.7)	36 (78.3)
Tumor invasion				1.551	0.213
T1–T2	30	11 (36.7)	19 (63.3)
T3–T4	62	15 (24.2)	47 (75.8)
Lymph node metastasis				4.429	0.035
N0	55	20 (36.4)	35 (63.6)
N+	37	6 (16.2)	31 (83.8)
TNM stage				8.106	0.017
I	10	6 (60.0)	4 (40.0)
II	36	12 (33.3)	24 (66.7)
III	46	8 (17.4)	38 (82.6)

Note: Bold values indicate statistical significance (P<0.05).

Abbreviation: GRP78, glucose-regulated protein 78.

Table 2 Univariate and multivariate analyses of different prognostic factors in patients with ESCC by Cox regression model

Clinicopathological features	Univariate analysis		Multivariate analysis
	P-value	HR (95% CI)	P-value	HR (95% CI)
Gender
Male vs female	0.040	0.522 (0.283–0.965)	0.241	1.447 (0.780–2.684)
Age (years)
<65 vs ≥65	0.265	1.329 (0.806–2.189)
Smoking status
None vs yes	0.017	0.514 (0.293–0.899)	0.147	0.652 (0.366–1.162)
Alcohol consumption status
None vs yes	0.135	0.674 (0.401–1.136)
Tumor location
Upper vs middle vs lower	0.241	0.655 (0.323–1.329)
Histological grade
G1 vs G2 vs G3	0.173	0.733 (0.468–1.146)
Tumor size (cm)
<4 vs ≥4	0.045	1.685 (1.013–2.805)	0.131	1.503 (0.886–2.550)
Tumor invasion
T1–T2 vs T3–T4	0.000	3.315 (1.756–6.256)	0.002	2.869 (1.489–5.526)
Lymph node metastasis
N0 vs N+	0.002	2.267 (1.367–3.761)	0.032	1.689 (1.004–2.841)
GRP78 expression
Low vs high	0.037	1.949 (1.069–3.551)	0.011	0.475 (0.251–0.898)
Adjuvant therapy
None vs yes	0.173	1.415 (0.859–2.322)

Note: Bold values indicate statistical significance (P<0.05).

Abbreviations: ESCC, esophageal squamous cell carcinoma; GRP78, glucose-regulated protein 78; HR, hazard ratio; CI, confidence interval.

Figure 4 Downregulating GRP78 expression could inhibit the invasion and migration abilities of ESCC cells in vitro.

Notes: Matrigel invasion assay and Transwell migration assay of the ESCC cell lines. TE-1 and CaEs-17 transfected with GRP78 siRNA (si-GRP78) and negative control siRNA (si-con). (A) TE-1 cells and (B) CaEs-17 cells.
Abbreviations: ESCC, esophageal squamous cell carcinoma; GRP78, glucose-regulated protein 78; siRNA, small interfering RNA.