Evaluation of long-chain acyl-coenzyme A synthetase 4 (ACSL4) expression in human breast cancer

Abstract

Background and purpose: Breast cancer (BC) is one of the major causes of female cancer-related death. It has recently been demonstrated that metabolic reprogramming including alteration in lipid metabolism is indicated in various types of cancer. The enzymes of the acyl-coenzyme A synthetase long-chain family (ACSLs) are responsible for converting fatty acids to their corresponding fatty acyl-coenzyme A esters which are essential for some lipid metabolism pathways. ACSL4 is one of the isoforms of ACSLs and has a marked preference for arachidonic and eicosapentaenoic acids. The objective of this study was to evaluate ACSL4 expression, its prognostic significance, and its correlation with p53 tumor suppressor in BC patients.

Experimental approach: In this study 55 pairs of fresh samples of BC and adjacent non-cancerous tissue were used to analyze ACSL4 expression, using real-time polymerase chain reaction and immunohistochemistry (IHC) staining. The expression of other studied variables was also examined using the IHC technique.

Findings / results: ACSL4 expression was significantly higher in BC tissues compared to the adjacent normal tissue. This upregulation was negatively correlated with Ki-67 and age, and positively correlated with p53 status. The correlation between ACSL4 and p53 may indicate the role of p53 in the regulation of lipid metabolism in cancer cells, in addition to its role in the regulation of ferroptosis cell death.

Conclusion and implications: Our results indicated that the expression of ACSL4 may be considered as a prognostic indicator and potential therapeutic target in BC. However, further studies are needed to confirm the significance of these findings.

Keywords: ACSL4; Breast cancer; Tumor suppressor; p53.

Fig. 1

Expression of ACSL4 mRNA in breast cancer tissues and adjacent normal tissues. Real-time polymerase chain reaction was performed to evaluate the expression level of ACSL4. The mRNA expression data were normalized to the beta-actin (ACTB) signal and (A) the comparison of the mRNA expression of ACSL4 was shown as Box plot; (B and C) the fold change of ACSL4 expression in each sample pair was calculated using 2-ΔΔCT as columns, mean ± SEM. *P < 0.01 Indicates significant difference with normal group.

Fig. 2

Photomicrograph images of immunohistochemistry staining of ACSL4 in sections of (A) breast tumor tissue and (B) the adjacent normal breast tissue. Brown staining shows the expression of ACSL4 in breast tumor tissues. The quantification of ACSL4 protein was evaluated using ImageJ (ver. 1.52h) software by Olympus light microscope with ×40 amplification (Pix/μm²). *P < 0.05 Indicates significant difference with normal group.

Fig. 3

Relationship between p53 and clinicopathological variables of breast cancer. Results are according to chi-square test. Marked groups have significant association with p53 status, *P < 0.05. p53 positive was considered as mutant and p53 negative as wild-type. ER, Estrogen receptor; PR, progesterone receptor; HER, human epidermal growth factor receptor-2.

Fig. 4

Relationship between Ki-67 and clinicopathological variables of breast cancer. Results are according to chi-square test. Marked groups have significant association with ki-67 expression. *P < 0.05. Ki-67 is reported as percent of expression. ER, Estrogen receptor; PR, progesterone receptor; HER, human epidermal growth factor receptor-2.