# A Comparison Study on the Metabolites in PC-3, RWPE-1, and Chrysin-Treated PC-3 Cells
## 1 Introduction  
Prostate cancer is a threat to human health worldwide. In 2020, prostate cancer was the second most commonly diagnosed cancer and the fifth leading cause of cancer-related deaths among men worldwide in 2020 [1].  
Prostate cancer screening tests and diagnoses include digital rectal examination, prostate-specific antigen (PSA) testing, ultrasound, magnetic resonance imaging (MRI), and prostate biopsy [2]. Except for the PSA test, these tests cause discomfort to the patient, as they involve examining the rectum. The PSA test is mainly used for cancer detection through blood tests because PSA is produced in the prostate and semen, and small amounts of PSA circulate in the blood. Prostate cancer can cause elevated PSA levels, but many non-cancerous conditions can also increase PSA levels. Therefore, the PSA level does not provide precise diagnostic information, making the diagnosis difficult using the PSA test alone. Thus, there is a need to develop diagnostic tests that minimize patient discomfortduring examination and adequate biomarkers that are more accurate, sensitive, and specific for the detection of prostate cancer.  
Metabolomics is a quantitative study that measures low-molecular-weight metabolites such as nutrients, drugs, and signaling mediators in an organism at a specified time under specific environmental conditions [3]. Recently, metabolomics has received increased attention for its application in early cancer diagnosis [4] because the occurrence and development of cancer can cause changes to the metabolome of the human body. Metabolomics is a powerful tool for identifying cancer biomarkers and improving cancer diagnosis, monitoring, and treatment [5]. Metabolomic studies generally employ nuclear magnetic resonance (NMR) spectroscopy, high-performance liquid chromatography/mass spectrometry (HPLC/MS), Fourier-transform infrared (FT/IR) spectroscopy, and gas chromatography-mass spectrometry (GC/MS) [6].  
Anticancer effects such as apoptotic effect [7], anti-inflammatory effect [8], anti-proliferative effect [9], and target of cancer-promoting transcription factors [10] of chrysin have been reported in various cancers, including prostate cancer, ovarian cancer, and breast cancer. In this study, chrysin was evaluated for metabolomic applications in cancer treatment monitoring. Metabolic differences between normal prostate, prostate cancer, and chrysin-treated PC-3 (PC-3 Chr) cells were analyzed using GC-MS to identify prostate cancer-specific metabolites and evaluate the monitoring of cancer treatment.  
Exploring alterations in metabolite profiles following treatment with anticancer agents can reveal potential biomarkers for assessing drug efficacy and responses. In this study, we compared the metabolic profiles of PC-3 cells, a widely used prostate cancer cell line, and PC-3 Chr cells. We evaluated the differences in metabolites between the untreated and PC-3 Chr cells to elucidate the metabolic alterations induced by this therapeutic intervention.  
We also analyzed metabolites in benign prostatic hyperplasia (BPH) cells. BPH, a non-cancerous condition characterized by increased PSA levels, served as an essential control in our study. Comparison of the metabolite profiles of PC-3 cells, PC-3 Chr cells, and BPH cells enabled us to discern specific metabolic changes associated with prostate cancer and distinguish them from those occurring in benign conditions.