New Selective Progesterone Receptor Modulators and Their Impact on the RANK/RANKL Complex Activity

Area of Science:

• Oncology
• Endocrinology
• Cell Biology

Background:

• Breast cancer treatment, including chemotherapy and hormone therapy, can lead to bone density loss and skeletal disruption.
• The RANK and RANKL proteins are crucial for osteoclast formation and play a significant role in mammary stem cell biology and breast cancer cell proliferation.
• The progesterone-induced RANKL signaling pathway regulates mammary epithelial cell growth, and its dysregulation contributes to breast cancer expansion.

Purpose of the Study:

• To investigate the potential of selective estrogen receptor modulators (SPRMs) with antiprogestin activity as novel anti-RANK agents.
• To evaluate the impact of SPRMs on the RANK-RANKL protein interaction and their effect on breast cancer cell proliferation.
• To analyze the downstream effects of SPRMs on NFkB and cyclin D1 expression.

Main Methods:

• Testing SPRMs with anti- and mesoprogestin functions for their interaction with RANK-RANKL.
• Analyzing breast cancer cell proliferation in response to RANKL stimulation and SPRM treatment.
• Assessing the expression of NFkB and cyclin D1 following SPRM administration.

Main Results:

• SPRMs demonstrated competitive interaction with RANK, inhibiting RANK-RANKL binding.
• Treatment with asoprisnil and ulipristal (SPRMs) resulted in inhibition of NFkB expression.
• SPRMs effectively limited cyclin D1 expression and exhibited paracrine anti-proliferative activity.

Conclusions:

• SPRMs with antiprogestin properties show promise as anti-RANK agents by disrupting the RANKL signaling pathway.
• These compounds exhibit anti-proliferative effects on breast cancer cells and may offer a therapeutic strategy for breast cancer with co-existing osteoporosis.
• Further research is warranted to confirm the anti-RANK activity and therapeutic potential of SPRMs in breast cancer treatment.