Expression level of VLDL receptor and VLDL-c levels in the malignant and benign breast tumors: The correlation with miRNA-4465 and miRNA-1297

Breast cancer as one of the most prevalent cancers has high morbidity and mortality. Very low-density lipoprotein receptor (VLDLR) is a multifunctional receptor which plays a principal role in the tumor development through affecting cell metastasis and proliferation. The VLDLR as a target for miRNA-4465 and miRNA-1297 was predicted using bioinformatics analysis. Tissue specimens of malignant (n = 50), benign (n = 35) and corresponding normal breast (n = 20) were considered to evaluate the expression of VLDLR using RT-qPCR and western blotting. The VLDL cholesterol (VLDL-C) levels were quantified using a colorimetric assay. The relative VLDLR expression was found in the malignant tumors, which was significantly lower than that in the normal tissues (P<0.05). The expression levels of VLDLR had no significant difference between malignant and benign tissues (P>0.05). Correlation analysis revealed that the VLDLR expression level had a direct correlation with miRNA-1297 (R=0.566, P<0.05), but a reverse one with miRNA-4465 (R = -0.663, P<0.0001). The VLDL-C level in the malignant and normal tissues was lower than that in the benign tumors, which was not significant (P>0.05). The expression levels of VLDLR in E⁺P-H^- (ER⁺,PR^-,HER2^-) tumors were higher than those in other subtypes (P<0.05). Furthermore, a negative correlation was found between the VLDLR expression level and the Ki 67% score. These data revealed that the lower expression of VLDLR mediated by the high expression levels of miRNA-4465 may be involved in the development of breast cancer. These results might provide some evidence for the effect of VLDLR on the breast cancer.