Analysis of the Expression of Dopamine Receptors, DRD1 and DRD5, in Cancerous Tissue of Patients with Breast Cancer and the Impact of Quercetin on the Expression of These Receptors in Hs578t and HDF Cell Lines

Background Objectives: The expression of neurotransmitters during cancer progression is one of the factors to consider. This study aimed to evaluate the possible expression changes in dopamine receptors (DRD1 and DRD5), in breast tumor tissue compared to healthy adjacent samples, and the effect of quercetin on the expression of these receptors. Materials Methods: Expression levels of DRD1 and DRD5 were evaluated in 20 breast tumors and healthy adjacent samples using qPCR. The RNA was extracted from all samples, followed by cDNA synthesis and real-time PCR. In vitro experiment was accomplished on breast cancer cell line, Hs578t. Cells were treated with quercetin and evaluated cell viability by MTT assay. DRD1 and DRD5 gene expression was performed in treatment cells compared to untreated control. Statistical analysis was performed to determine the significance. Results: The results showed that the DRD1 and DRD5 were unregulated in breast cancer tissue (p 0.01). For cellular experiment, MTT assays revealed that the quercetin induced a significant decrease in cell viability and proliferation in dose and time-dependent but it was not seen in a normal cell line (HDF). Hs578t cells showed a significant reduction of DRD5 in response to quercetin. DRD1 gene downregulation was indicated significant in 72h treatment. Conclusions: The effect of quercetin on the expression of genes encoding DRD1 and DRD5 showed that this substance reduced the expression of these two genes in treated Hs578t cells compared to untreated cells in the same cell line.