Polo-like kinase 3 is associated with poor prognosis and regulates proliferation and metastasis in prostate cancer

Figures & data

Figure 1 The disease-free survival rates of all patients and non-metastatic patients.

Notes: (A) All patients (low Plk3 expression [N=324, 65%], high Plk3 expression [N=167, 33%]) and (B) non-metastatic patients (low Plk3 expression [N=292, 58%], high Plk3 expression [N=158, 32%]) with prostate cancer were compared according to low- and high-Plk3 status. Statistical significance was determined using the log-rank test.

Abbreviation: Plk3, polo-like kinase 3.

Table 1 Prognostic value of Plk3 expression for the disease-free survival by Cox proportional hazards model

Variables	Disease-free survival
	HR (95% CI)	P-value
Univariate analysis
Age (≥60 vs <60 years)	1.488 (0.968–2.287)	0.070
Gleason score (>7 vs =7 vs < 7)	9.464 (1.319–67.921)	0.025*
Tumor stage (T2–T4 vs T1)	2.972 (1.732–5.102)	<0.001***
Lymph node stage (N1 vs N 0)	1.801 (1.111–2.920)	0.017
Distant metastasis (M1 vs M0)	0.049 (0–2488134.592)	0.740
PSA (≥4 vs <4)	3.410 (1.644–7.075)	0.001**
Plk3 expression (high vs low)	1.855 (1.048–3.285)	0.034*
Multivariate analysis
Gleason score (>7 vs = 7 vs < 7)	5.709 (0.789–41.328)	0.085
Tumor stage (T2–T4 vs T1)	2.763 (1.1607–4.751)	<0.00024***
Plk3 expression (high vs low)	1.933 (1.091–3.639)	0.025*

Note:

* P<0.05,

** P<0.01, and

*** P<0.001. Statically significant P-values are shown in bold.

Abbreviations: Plk3, polo-like kinase 3; PSA, prostate-specific antigen.

Figure 2 Plk3 knockdown reduces prostate cancer cell proliferation.

Notes: (A) Western blotting verification of si-Plk3 knockdown efficiency of DU145 cells. (B) GSEA of proliferation-associated gene set in Plk3 high (H) and low (L) expression groups. The samples were classified into low (mRNA expression <136) or high (mRNA expression >136) based on the average. (C) MTS assay evaluation of influence of Plk3 knockdown on DU145 viability. (D) Colony formation assay determining the effect of Plk3 knockdown in DU145 cells. (E) FCM assay evaluation of influence of Plk3 knockdown on DU145 apoptosis. The data are presented as mean ± SD. *P<0.05 and **P<0.01.

Abbreviations: Ctrl, control; FCM, flow cytometry; GSEA, Gene Set Enrichment Analysis; n.s., no significance; Plk3, polo-like kinase 3.

Table 2 GeneSet: POSITIVE_REGULATION_OF_CELL_PROLIFERATION

	Probe	Description	Rank in gene list	Rank metric score	Running ES	Core enrichment
1	S1PR2	9,294	32	0.615	0.0207	Yes
2	LIF	3,976	53	0.576	0.0405	Yes
3	CDKN1A	1,026	69	0.557	0.0600	Yes
4	FOSL1	8,061	78	0.547	0.0794	Yes
5	CSF1	1,435	81	0.546	0.0990	Yes
6	SERTAD1	29,950	105	0.523	0.1168	Yes
7	CD86	942	122	0.512	0.1346	Yes
8	IL15	3,600	192	0.477	0.1485	Yes
9	FLT3LG	2,323	214	0.467	0.1643	Yes
10	FGF18	8,817	333	0.435	0.1743	Yes

Abbreviation: ES, enrichment score.

Figure 3 Plk3 knockdown inhibits prostate cancer cell migration

Notes: (A) GSEA of metastasis-associated gene sets in the Plk3 high (H) and low (L) expression groups. The samples were as low (mRNA expression <136) or high (mRNA expression <136) based on the average. (B) Migration assay measurement of influence of Plk3 knockdown on DU145 mobility. (C) Wound healing assay measurement of influence of Plk3 knockdown on DU145 mobility. (D) Western blot evaluation of influence of Plk3 knockdown on metastasis-associated protein. The results are presented as mean ± SD. *P<0.05,**P<0.01, and ***P<0.001.

Abbreviations: Ctrl, control; GSEA, Gene Set Enrichment Analysis; h, hours; Plk3, polo-like kinase 3.

Table 3 GeneSet: NAKAMURA_METASTASIS_MODEL_UP

	Probe	Description (from dataset)	Rank in gene list	Rank metric score	Running ES	Core enrichment
1	DUSP5	1,847	22	0.652	0.0748	Yes
2	FOSL1	8,061	78	0.547	0.1357	Yes
3	SLC16A3	9,123	164	0.488	0.1884	Yes
4	TUBB6	84,617	208	0.470	0.2410	Yes
5	LAPTM5	7,805	288	0.445	0.2889	Yes
6	HCLS1	3,059	336	0.433	0.3370	Yes
7	ADCY3	109	485	0.404	0.3768	Yes
8	GRK5	2,869	683	0.374	0.4107	Yes
9	GJB3	2,707	736	0.368	0.4510	Yes
10	CMTM3	123,920	838	0.354	0.4873	Yes

Abbreviation: ES, enrichment score.

Table 4 GeneSet: GILDEA_METASTASIS

	Probe	Description (from dataset)	Rank in gene list	Rank metric score	Running ES	Core enrichment
1	SRGN	5,552	17	0.664	0.0885	Yes
2	IFI16	3,428	70	0.555	0.1606	Yes
3	IGFBP4	3,487	171	0.485	0.2209	Yes
4	GBP1	2,633	248	0.455	0.2784	Yes
5	TIMP3	7,078	765	0.365	0.3022	Yes
6	RAC2	5,880	814	0.357	0.3479	Yes
7	PRKCDBP	112,464	956	0.339	0.3866	Yes
8	KRT7	3,855	1046	0.331	0.4268	Yes
9	SPARC	6,678	1140	0.322	0.4656	Yes
10	VAMP5	10,791	1184	0.317	0.5062	Yes