XBP1s Acts as a Tumor Suppressor to Inhibit the EMT Process and Metastasis of Papillary Thyroid Cancer

Figures & data

Table 1 Clinicopathological Characteristics of Patients with PTC

Characteristics		No. of Patients (%)
Patients		41
Age (years)	<55	36 (87.8)
	≥55	5 (12.2)
Gender	Male	22 (53.7)
	Female	19 (46.3)
Tumor size	1~2cm	41 (100)
Tumor focality	Unifocal	41 (100)
Extrathyroidal extension	No	41 (100)
Lymph node metastasis	N0	21 (51.2)
	N1	20 (48.8)

Table 2 Multivariate Survival Analysis of Risk Factors for Lymph Node Metastasis of PTC

Variable	Multivariate Analysis
	P-value	HR (95% CI)
Age (years)	0.417	0.968 (0.895~1.047)
Gender (female/male)	0.759	1.313 (0.231~7.473)
T (mm)	0.234	1.214 (0.882~1.669)
XBP1s expression (low/high)	0.003	0.066 (0.011~0.392)

Note: Bold and italic text values indicate P<0.05, which is statistically significant.

Figure 1 Low expression of XBP1s is closely related to lymph node metastasis in PTC. (A) Representative immunohistochemical staining profile of PTC tissue samples with (N1) or without (N0) lymph node metastasis. (B) The expression of XBP1s in N1 and N0 groups according to the SI of IHC. (C) ROC curve analyses to distinguish N1 patients. Differences between groups in (B) assay were analyzed by two-tailed Student’s T-test. Error bars represent means ± SD.

Table 3 Association of XBP1 Expression with Clinicopathologic Features in PTC Patients in TCGA

Parameter	Total n=451 (%)	XBP1 Expression		χ^2	P
		Low n=235 (%)	High n=216 (%)
Age (years)				2.418	0.120
< 55	299 (66.3)	148 (49.5)	151 (50.5)
≥ 55	152 (33.7)	87 (57.2)	65 (42.8)
Gender				4.810	0.028
Female	327 (72.5)	160 (48.9)	167 (51.1)
Male	124 (27.5)	75 (60.5)	49 (39.5)
Tumor size				2.095	0.148
≤2cm	164 (36.4)	79 (48.2)	85 (51.8)
>2cm	273 (60.5)	151 (55.3)	122 (44.7)
Tumor focality				0.053	0.817
Unifocal	183 (40.6)	102 (55.7)	81 (44.3)
Multifocal	135 (29.9)	77 (57.0)	58 (43.0)
T classification				13.369	0.000
T1-T2	272 (60.3)	121 (44.5)	151 (55.5)
T3-T4	170 (37.7)	106 (62.4)	64 (37.6)
Lymph node metastasis				9.984	0.002
N0	226 (50.1)	101 (44.7)	125 (55.3)
N1	225 (49.9)	134 (59.6)	91 (40.4)
Metastasis				0.636	0.425
M0	270 (59.9)	152 (56.3)	118 (43.7)
M1	7 (1.6)	5 (71.4)	2 (28.6)
Stage				18.234	0.000
I–II	294 (65.2)	132 (44.9)	162 (55.1)
III–IV	156 (34.6)	103 (66.0)	53 (34.0)
Histological type (TPC)				5.205	0.074
Classical/usual	332 (73.6)	181 (54.5)	151 (45.5)
Follicular	78 (17.3)	32 (41.0)	46 (59.0)
Tall cell	34 (7.5)	20 (58.8)	14 (41.2)

Note: Bold and italic text values indicate P<0.05, which is statistically significant.

Figure 2 Decreased XBP1 expression in PTC tissue is associated with patient prognosis. (A–C) Relative levels of XBP1 transcripts in 505 TC, 230 TC whit N0, 58 TC with N1 and 59 non-tumor thyroid tissues in TCGA from UALCAN and original data. (D) (UALCAN), (E) (GEPIA) stratification analysis of XBP1 expression in the different stages of TC. (F and G) Kaplan–Meier curves showing the relationship of XBP1 expression to OS and DFS of patients with TC.

Figure 3 Overexpression of XBP1s reduces the invasive and metastatic potential of PTC cells, and inhibits EMT in PTC cells. (A) Cell migration and invasion assay. (B) Wound healing assay. Difference between two groups was tested using two-tailed Student’s T-test. Data are expressed as the mean ± SD of each group of cells from three separate experiments. *P<0.05; **P<0.01; ***P<0.001.

Figure 4 Overexpression of XBP1s inhibits EMT in PTC cells. (A) Correlation analysis between XBP1 and EMT-related markers (ZO-1, N-cadherin, E-cadherin and Vimentin) in TCGA (GEPIA). (B) Western blot analysis of the expression of XBP1s and EMT-related markers in PTC cells. (C) Immunofluorescence analysis of the expression of N-cadherin and E-cadherin in PTC cells. Difference between two groups was tested using two-tailed Student’s T-test. Data are expressed as the mean ± SD of each group of cells from three separate experiments. *P<0.05; **P<0.01; ***P<0.001, ^#P>0.05.