Overexpression of HDAC9 is associated with poor prognosis and tumor progression of breast cancer in Chinese females

Figures & data

Table 1 Association of HDAC9 expression with the clinical features of breast cancer patients

Features	Total (N=118)	HDAC9 expression		P-value
		Low (n=54)	High (n=64)
Age (years)				0.763
≤50	42	20	22
>50	76	34	42
Tumor size (cm)				0.360
≤3	45	23	22
>3	73	31	42
ER status				0.264
Negative	46	24	22
Positive	72	30	42
PR status				0.129
Negative	48	26	22
Positive	70	28	42
HER2 status				0.360
Negative	45	23	22
Positive	73	31	42
LN metastasis				0.021
Negative	52	30	22
Positive	66	24	42
TNM stage				0.004
I–II	55	33	22
III–IV	63	21	42

Abbreviations: ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; LN, lymph node; PR, progesterone receptor.

Figure 1 The mRNA expression of HDAC9 measured by qRT-PCR.

Notes: (A) HDAC9 expression in breast cancer tissues and paired normal tissues. The expression of HDAC9 was higher in breast cancer tissues than that in the matched normal tissues (***P<0.001). (B) HDAC9 expression in cells. The expression of HDAC9 was increased in breast cancer cells compared with the normal cells (**P<0.01, ***P<0.001).
Abbreviation: qRT-PCR, quantitative real-time polymerase chain reaction.

Table 2 Univariate and multivariate Cox analysis for HDAC9 in breast cancer patients

Characteristics	Univariate analysis			Multivariate analysis
	HR	95% CI	P-value	HR	95% CI	P-value
HDAC9	2.996	1.611–5.572	0.001	2.996	1.611–5.572	0.001
Age	1.117	0.646–1.930	0.692	–	–	–
Tumor size	1.243	0.726–2.129	0.428	–	–	–
ER status	0.996	0.582–1.704	0.989	–	–	–
PR status	0.916	0.537–1.562	0.748	–	–	–
HER2 status	1.291	0.744–2.240	0.363	–	–	–
Lymph node metastasis	1.236	0.710–2.151	0.454	–	–	–
TNM stage	0.870	0.509–1.489	0.612	–	–	–

Abbreviations: ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; HR, hazard ratio; PR, progesterone receptor.

Figure 2 Kaplan–Meier survival curves for breast cancer patients based on the expression of HDAC9.

Notes: P-value was calculated using the log-rank test. Patients with high HDAC9 expression had shorter survival time than those with low HDAC9 expression (log-rank P<0.05).

Figure 3 Expression of HDAC9 in cells treated with siRNA or SAHA.

Notes: (A) HDAC9 expression was significantly decreased in MCF-7 transfected with HDAC9 siRNA and MCF-7 treated with SAHA compared with the controls (**P<0.01, ***P<0.001). (B) HDAC9 expression was significantly decreased in BT474 transfected with HDAC9 siRNA and BT474 treated with SAHA compared with the controls (**P<0.01).
Abbreviations: DMSO, dimethyl sulfoxide; SAHA, suberoylanilide hydroxamic acid.

Figure 4 Effects of HDAC9 expression on cell proliferation, migration and invasion of breast cancer cells.

Notes: (A, B) Cell proliferation was suppressed by HDAC9 knockdown in MCF-7 and BT474 cells (*P<0.05, **P<0.01). (C, D) Number of migrated cells was decreased by a reduction of HDAC9 in breast cancer cells (**P<0.01, ***P<0.001). (E, F) Cell invasion was inhibited by the downregulation of HDAC9 in both MCF-7 and BT474 cells (**P<0.01).
Abbreviations: DMSO, dimethyl sulfoxide; SAHA, suberoylanilide hydroxamic acid.