Upregulation of long noncoding RNA LOC440040 promotes tumor progression and predicts poor prognosis in patients with prostate cancer

Figures & data

Figure 1 Relative LOC440040 expression levels in PCa tissues and cell lines.

Notes: (A) A microarray containing 8,277 lncRNA probes was used to identify differentially expressed lncRNAs in three PCa patients. (B) Relative LOC440040 expression level in PCa tissues compared with paired adjacent normal tissues. (C) Relative LOC440040 expression level in two PCa cell lines (PC-3, 22RV1) and normal prostate cell line (WPMY-1). *P<0.05.
Abbreviations: lncRNA, long noncoding RNA; PCa, prostate cancer.

Table 1 Correlation between LOC440040 expression and different clinicopathological features in patients with PCa

Characteristics	Group	Total (%)	LOC440040 expression		P-value
			High (%)	Low (%)
Age (years)	<65	23 (31.9)	16 (69.6)	7 (30.4)	0.396
	≥65	49 (68.1)	29 (59.2)	20 (40.8)
Tumor size (cm)	<2.5	43 (59.7)	27 (62.8)	16 (37.2)	0.951
	≥2.5	29 (40.3)	18 (62.1)	11 (37.9)
Gleason score	<7	21 (29.2)	9 (42.9)	12 (57.1)	0.027
	≥7	51 (70.8)	36 (70.6)	15 (29.4)
Preoperative PSA level (ng/mL)	<10	19 (26.4)	7 (36.8)	12 (63.2)	0.007
	≥10	53 (73.6)	38 (71.7)	15 (28.3)
Clinical stage	T2	52 (72.2)	32 (61.5)	20 (38.5)	0.786
	T3–T4	20 (27.8)	13 (65.0)	7 (35.0)
Lymph node metastasis	Negative	59 (81.9)	36 (61.0)	23 (39.0)	0.580
	Positive	13 (18.1)	9 (69.2)	4 (30.8)
Multiple lesions	Negative	38 (52.8)	22 (57.9)	16 (42.1)	0.393
	Positive	34 (47.2)	23 (67.6)	11 (32.4)

Abbreviations: PCa, prostate cancer; PSA, prostate-specific antigen.

Figure 2 Kaplan–Meier survival curves of patients with PCa based on LOC440040 expression status (P<0.001, log-rank test).

Note: Patients in the high LOC440040 expression group exhibited significantly poorer prognosis than those in the low LOC440040 expression group.
Abbreviation: PCa, prostate cancer.

Table 2 Univariate and multivariate analyses of biochemical recurrence-free survival (Cox proportional hazards regression model)

Variable	Univariate analysis		Multivariate analysis
	HR (95% CI)	P-value	HR (95% CI)	P-value
Age (years)
≥65 vs <65	1.063 (0.614–1.838)	0.828
Tumor size (cm)
≥2.5 cm vs <2.5 cm	1.489 (0.881–2.515)	0.137
Gleason score
≥7 vs <7	3.115 (1.622–5.985)	0.001	3.352 (1.665–6.750)	0.001
Preoperative PSA level
≥10 vs <10 (ng/mL)	1.497 (0.824–2.720)	0.185
Clinical stage
T3–T4 vs T2	1.048 (0.581–1.890)	0.876
Lymph node metastasis
Positive vs negative	3.393 (1.720–6.693)	<0.001	3.735 (1.801–7.743)	<0.001
Multiple lesions
Positive vs negative	2.788 (1.639–4.744)	<0.001	4.109 (2.305–7.325)	<0.001
LOC440040 expression
High vs low	3.625 (2.050–6.412)	<0.001	4.871 (2.604–9.110)	<0.001

Abbreviations: HR, hazard ratio; CI, confidence interval; PSA, prostate-specific antigen.

Figure 3 Effects of LOC440040 knockdown on PCa cell proliferation.

Notes: (A and B) Expression of LOC440040 in PC-3 and 22RV1 cells was significantly downregulated after si-LOC440040 transfection. (C and D) Cell proliferation was measured by CCK-8 assay in PC-3 and 22RV1 cells transfected with si-LOC440040 or si-NC. *P<0.05.
Abbreviations: CCK-8, Cell Counting Kit-8; OD, optical density; PCa, prostate cancer; si-NC, negative control siRNA; siRNA, short interfering RNA.

Figure 4 Effects of LOC440040 knockdown on PCa cell proliferation.

Notes: (A and B) Colony formation assay was performed to determine the proliferation of PC-3 and 22RV1 cells after si-LOC440040 transfection. (C–G) Western blot protein expression levels in PC-3 and 22RV1 cells after si-LOC440040 transfection. GAPDH protein was used as an internal control. *P<0.05.
Abbreviations: PCa, prostate cancer; si-NC, negative control siRNA; siRNA, short interfering RNA.

Figure 5 Effects of LOC440040 knockdown on PCa cell migration and invasion.

Notes: (A and B) The Transwell migration assay showed that the number of migrated cells was significantly lower in the si-LOC440040-transfected group than in the si-NC-transfected group. (C and D) The Transwell invasion assay showed that the number of invaded cells was significantly lower in the si-LOC440040-transfected group than in the si-NC-transfected group. (E–G) Western blot protein expression levels in PC-3 and 22RV1 cells after si-LOC440040 transfection. GAPDH protein was used as an internal control. *P<0.05.
Abbreviations: PCa, prostate cancer; si-NC, negative control siRNA; siRNA, short interfering RNA.