Vitamin D3 suppresses the cholesterol homeostasis pathway in patient-derived glioma cell lines

Area of Science:

• Oncology
• Biochemistry
• Molecular Biology

Background:

• Glioblastoma is a highly aggressive brain tumor with limited treatment options.
• Vitamin D and its active form, calcitriol, have demonstrated potential anti-cancer properties.
• The Vitamin D Receptor (VDR) is known to mediate many cellular effects of vitamin D.

Purpose of the Study:

• To investigate the differential effects of vitamin D3 and calcitriol on patient-derived glioblastoma cell lines.
• To elucidate the role of the Vitamin D Receptor (VDR) in mediating vitamin D's anti-cancer activity in glioblastoma.
• To identify the molecular mechanisms underlying vitamin D3's impact on glioblastoma cell growth.

Main Methods:

• Utilized patient-derived glioma cell lines for experimental studies.
• Performed gene silencing and gene knockout experiments to assess VDR function.
• Conducted RNA sequencing and sterolomics analyses to explore molecular pathways.

Main Results:

• Vitamin D3 exhibited a more potent inhibitory effect on glioblastoma cell viability and proliferation compared to calcitriol.
• VDR expression levels and function did not influence the sensitivity of glioblastoma cells to vitamin D3.
• Vitamin D3 was found to inhibit cholesterol synthesis by downregulating 7-dehydrocholesterol reductase, leading to sterol intermediate accumulation.

Conclusions:

• Vitamin D3, not calcitriol, effectively inhibits patient-derived glioblastoma cell growth.
• The anti-cancer effects of vitamin D3 in glioblastoma are VDR-independent.
• Vitamin D3 exerts its inhibitory action by disrupting cholesterol homeostasis and synthesis pathways.