Knockdown of STIM1 expression inhibits non-small-cell lung cancer cell proliferation in vitro and in nude mouse xenografts

Figures & data

Table 1. Association of STIM1 expression with clinicopathological factors in NSCLC and benign pulmonary diseases.

Clinicopathological parameter	N	STIM1-positive n (%)	P-value
Benign lesions	187	35 (18.72)	0.000
NSCLC	352	271 (76.99)
Gender
Male	248	194 (80.24)	0.394
Female	104	77 (69.23)
Age, years
≤65	280	215 (76.79)	0.144
>65	72	61 (84.72)
Histology
Squamous cell	151	110 (72.85)	0.110
Adenocarcinoma	201	161 (80.10)
Differentiation
High	59	47 (79.66)	0.789
Middle	214	165 (77.10)
Low	79	59 (74.68)
AJCC stage
I	167	119 (71.26)	0.038
II	77	61 (79.22)
IIIa	108	91 (84.26)
Lymph node metastasis
No	179	138 (77.09)	0.961
Yes	173	133 (76.88)

Figure 1. Expression of STIM1 in NSCLC and benign pulmonary diseases tissues. (a) Hematoxylin and eosin staining of lung adenocarcinoma. (b) Immunohistochemical staining of STIM1 protein in the cytoplasm of NSCLC cells. (c) Hematoxylin and eosin staining of tissues from a benign pulmonary disease. (d) Negative immunostaining for the STIM1 protein in a benign pulmonary disease. Scale bar: 20 μm. STIM1, stromal interaction molecule 1; NSCLC, non-small-cell lung cancer.

Figure 2. Expression and knockdown of STIM1 expression in NSCLC cell lines. (a) The expressiom of STIM1 in 11 NSCLC cell lines were detected by Western blotting. (b) and (c) Western blotting analysis of STIM1 expression in A549 and SK-MES-1 cells infected with STIM1 shRNA lentivirus. α-Tubulin as used as a loading control. STIM1, stromal interaction molecule 1; NSCLC, non-small-cell lung cancer.

Figure 3. Knockdown of STIM1 inhibits cell growth and viability of NSCLC cells. (a) STIM1 knockdown significantly inhibited cell growth in A549 and SK-MES-1 cells detected by cell counting assay. (b) MTS assay detected that the viability of NSCLC cells infected STIM1-shRNA was suppressed. (c) STIM1 knockdown A549 and SK-MES-1 cells also formed significantly less colonies than those of their control cells. *p < 0.05 by Student’s t-test. STIM1, stromal interaction molecule 1. a. b. c.

Figure 4. Knockdown of STIM1 expression induced cell cycle block in NSCLC cells. The cell cycle distribution was investigated in A549 and SK-MES-1 cells with STIM1 knockdown and it was observed that the S and G2/M phase population was markedly increased, while the G0/G1 phase population was significantly decreased compared with their controls. (a) Flow cytometric assay for A549 cells. (b) Flow cytometric assay for SK-MES-1 cells. *p < 0.05 by Student’s t-test. STIM1, stromal interaction molecule 1.

Figure 5. Expression of cell cycle-related molecules in NSCLC cells with STIM1 knockdown. CDK1 and CDK2 were significantly downregulated after knockdown of STIM1 expression in A549 and SK-MES-1 cells. *p < 0.05 by Student’s t-test. STIM1, stromal interaction molecule 1; NSCLC, non-small-cell lung cancer.

Figure 6. Knockdown of STIM1 expression inhibits A549 cells in nude mouse xenografts. Knockdown of STIM1 inhibited tumorigenicity and growth of A549 cells in nude mice xenografts (a) Growth curve of tumor xenografts. (b) Volume of tumor xenografts. (c) Wet weights of tumor xenografts. *P < 0.05 compared with A549 and Scr-shRNA-infected A549 cells. *p < 0.05 by Student’s t-test. STIM1, stromal interaction molecule 1; NSCLC, non-small-cell lung cancer.