Comparative miRNA Expression Profiling Reveals Candidates Involved in Prostate Cancer Radioresistance

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Prostate cancer is a leading global malignancy in men, with treatment outcomes heavily influenced by tumor radiosensitivity.
• MicroRNAs (miRNAs) are critical regulators of cellular processes including proliferation, apoptosis, and DNA damage response, and are increasingly recognized for their role in therapeutic resistance.
• The specific involvement of miRNAs in prostate cancer radioresponse remains an area requiring further investigation.

Purpose of the Study:

• To investigate the expression patterns of ten selected miRNAs previously associated with radiation resistance in other cancer types within prostate cancer models.
• To determine if distinct miRNA expression profiles can differentiate between radiation-resistant and radiation-sensitive prostate cancer cells.

Main Methods:

• Radiation-resistant (PC-3) and radiation-sensitive (LNCaP) prostate cancer cell lines, along with normal prostate epithelial cells (hPTEC), were exposed to varying doses of ionizing radiation (0-8 Gy).
• Quantitative PCR was employed to analyze miRNA expression levels, utilizing SNORD48 as an internal control and the 2−ΔΔCt method for quantification.
• Statistical analysis focused on identifying dose-dependent and differential expression patterns of selected miRNAs between cell lines.

Main Results:

• In radiation-resistant PC-3 cells, miR-20a-5p, miR-128-3p, and miR-135b-5p exhibited significant dose-dependent upregulation, with miR-128-3p showing a positive correlation with radiation dose.
• Conversely, miR-23b-3p and miR-381-3p were significantly downregulated in PC-3 cells, demonstrating a negative correlation with radiation dose.
• LNCaP cells displayed only moderate and non-dose-dependent changes in miRNA expression, highlighting distinct molecular signatures compared to PC-3 cells.

Conclusions:

• Distinct miRNA expression signatures effectively differentiate radiation-resistant from radiation-sensitive prostate cancer cells.
• Upregulated miRNAs, including miR-20a-5p and miR-128-3p, are potential contributors to prostate cancer radioresistance.
• Downregulated miRNAs, such as miR-23b-3p and miR-381-3p, may function as radiosensitizers, offering potential therapeutic targets for enhancing radiation efficacy.