Letrozole and zoledronic acid changed signalling pathways involved in the apoptosis of breast cancer cells

The recent progress of endocrine therapy-induced osteoporosis in estrogen-positive breast cancer therapy

Breast cancer is a significant global health concern, and the discovery of endocrine therapy has played a crucial role in the treatment of estrogen-positive breast cancer. However, these therapies are often associated with osteoporosis-related adverse events, which increase the risk of fractures in breast cancer patients and can result in limited mobility and reduced quality of life. Previous studies have shown that osteoporosis is essential side effects of the breast cancer therapy, although the exact mechanisms remain mostly unclear. Current clinical treatments, such as bisphosphonates, cause side effects and may impact the therapeutic response to endocrine drugs. In this review, we explore the likelihood of endocrine therapy-induced osteoporosis in estrogen-positive breast cancer therapy and discuss the involved mechanisms as well as the therapeutic potential of drugs and drug combination strategies.

Cholesterol and Its Derivatives: Multifaceted Players in Breast Cancer Progression

Cholesterol is an essential lipid primarily synthesized in the liver through the mevalonate pathway. Besides being a precursor of steroid hormones, bile acid, and vitamin D, it is an essential structural component of cell membranes, is enriched in membrane lipid rafts, and plays a key role in intracellular signal transduction. The lipid homeostasis is finely regulated end appears to be impaired in several types of tumors, including breast cancer. In this review, we will analyse the multifaceted roles of cholesterol and its derivatives in breast cancer progression. As an example of the bivalent role of cholesterol in the cell membrane of cancer cells, on the one hand, it reduces membrane fluidity, which has been associated with a more aggressive tumor phenotype in terms of cell motility and migration, leading to metastasis formation. On the other hand, it makes the membrane less permeable to small water-soluble molecules that would otherwise freely cross, resulting in a loss of chemotherapeutics permeability. Regarding cholesterol derivatives, a lower vitamin D is associated with an increased risk of breast cancer, while steroid hormones, coupled with the overexpression of their receptors, play a crucial role in breast cancer progression. Despite the role of cholesterol and derivatives molecules in breast cancer development is still controversial, the use of cholesterol targeting drugs like statins and zoledronic acid appears as a challenging promising tool for breast cancer treatment.