The role of microRNA-21 in predicting brain metastases from non-small cell lung cancer

Figures & data

Table 1 Clinicopathological characteristics of NSCLC patients with or without brain metastases

Characteristic	BM+ group (n=68)	BM− group (n=64)	P-value
Age (years)	58.5±10.2	61.8±11.4	0.082
Gender			0.325
Male	48	40
Female	20	24
Smoking history			0.939
Yes	44	41
No	24	23
Pathological type			0.053
Adenocarcinoma	55	43
Squamous carcinoma	10	10
Sarcoma	2	2
Large cell carcinoma	1	1
Neuroendocrine carcinoma	0	8
Lymph node metastasis			0.510
Yes	40	34
No	28	30

Abbreviations: NSCLC, non-small cell lung cancer; BM+, NSCLC patients with brain metastases; BM−, NSCLC patients without brain metastases.

Table 2 The primer sequences of real-time qRT-PCR products

Target	Primer	Sequence
miR-21	RT	5′-GTCGTATCCAGTGCAGGGTCCGAGGTATTCGCACTGGATACGACTCAACA-3′
	Forward:	5′-GTGCAGGGTCCGAGGT-3′
	Reverse:	5′-GCCGCTAGCTTATCAGACTGATGT-3′
U6	RT	5′-AACGCTTCACGAATTTGCGT-3′
	Forward:	5′-CTCGCTTCGGCAGCACA-3′
	Reverse:	5′-AACGCTTCACGAATTTGCGT-3′

Abbreviations: miR-21, microRNA-21; RT, reverse transcription; qRT-PCR, quantitative real-time polymerase chain reaction.

Figure 1 Expression of miR-21 in NSCLC patients with or without BM detected by qRT-PCR.

Note: ***P<0.001.
Abbreviations: miR-21, microRNA-21; NSCLC, non-small cell lung cancer; BM, brain metastases; BM+, NSCLC patients with brain metastases; BM−, NSCLC patients without brain metastases; qRT-PCR, quantitative real-time polymerase chain reaction.

Figure 2 Correlation between the expression of miR-21 and the risk of BM in NSCLC patients. (A) The ROC curve analysis for the miR-21 expression in predicting BM from NSCLC; (B) Kaplan–Meier curve for the occurrence time to BM in NSCLC patients.

Abbreviations: miR-21, microRNA-21; NSCLC, non-small cell lung cancer; BM, brain metastases; ROC, receiver operating characteristic.

Figure 3 Expression of miR-21 in five human NSCLC cell lines (A549, NCI-H157, NCI-H460, YTMLC-90, and XWLC-05).

Abbreviations: miR-21, microRNA-21; NSCLC, non-small cell lung cancer.

Figure 4 Expression of miR-21 in A549 cells among three groups after transfection detected by qRT-PCR.

Note: **Compared with the NC group or mock group, P<0.01.
Abbreviations: miR-21, microRNA-21; qRT-PCR, real-time quantitative polymerase chain reaction; IN, inhibitor group; NC, negative control group; mock, mock group.

Figure 5 Effects of miR-21 inhibitors on the proliferation and clone formation of A549 cells. (A) The effect of miR-21 inhibitors on the proliferation of A549 cells detected by MTT assay; (B) the effect of miR-21 inhibitors on the clone formation of A549 cells measured by colony-forming assay (mean and standard deviation).

Notes: *Compared with the NC group or mock group, P<0.05; **compared with the NC group or mock group, P<0.01.
Abbreviations: miR-21, microRNA-21; IN, inhibitor group; NC, negative control group; mock, mock group; OD, optical density.

Figure 6 Effects of miR-21 inhibitors on cell cycle and apoptosis of A549 cells. (A) The effect of miR-21 inhibitors on cell cycle of A549 cells detected by FCM; (B) the effect of miR-21 inhibitors on apoptosis of A549 cells detected by FCM.

Note: *Compared with the NC group or mock group, P<0.05.
Abbreviations: miR-21, microRNA-21; FCM, flow cytometry; IN, inhibitor group; NC, negative control group; mock, mock group.

Figure 7 Effects of miR-21 inhibitors on the migration and invasion of A549 cells. (A) The effect of miR-21 inhibitors on the invasion of A549 cells detected by transwell assay; (B) the effect of miR-21 inhibitors on the migration of A549 cells detected by transwell assay.

Notes: **Compared with the NC group or mock group, P<0.01. Magnification was 200×.
Abbreviations: miR-21, microRNA-21; IN, inhibitor group; NC, negative control group; mock, mock group.

Figure 8 Effects of miR-21 inhibitors on angiogenesis of A549 cells. (A) The tube circumference of A549 cells in the three groups analyzed by ImageJ software; (B) the tube junctions of A549 cells in the three groups analyzed by ImageJ software.

Note: *Compared with the NC group or mock group, P<0.05.
Abbreviations: miR-21, microRNA-21; IN, inhibitor group; NC, negative control group; mock, mock group.