| The insulin-like growth factor-I receptor (IGF-IR) in breast cancer: biology and treatment strategies
Abstract Breast cancer is the most common cancer and the
second leading cause of cancer-related deaths among women
worldwide. Although patients are often diagnosed in the early
and curable stages, the treatment of metastatic breast cancer
remains a major clinical challenge. The combination of chemotherapy
with new targeting agents, such as bevacizumab, is
helpful in improving patient survival; however, novel treatment
strategies are required to improve clinical outcomes.
The insulin-like growth factor-I receptor (IGF-IR) is a tyrosine
kinase cell surface receptor which is involved in the regulation
of cell growth and metabolism. Previous studies have shown
that activation of the IGF-IR signaling pathway promotes proliferation,
survival, and metastasis of breast cancer cells.
Additionally, overexpression of IGF-IR is associated with
breast cancer cell resistance to anticancer therapies.
Recently, IGF-IR has been introduced as a marker of stemness
in breast cancer cells and there is also accumulating evidence
that IGF-IR contributes to the establishment and maintenance
of breast cancer epithelial-mesenchymal transition (EMT).
Therefore, pharmacological or molecular targeting of IGF-IR
could be a promising strategy, in the treatment of patients with
breast cancer, particularly in order to circumvent the therapeutic
resistance and targeting breast cancer stem/progenitors.
Currently, many strategies have been developed for targeting
IGF-IR, some have entered clinical trials and some are in
preclinical stages for breast cancer therapy. In this review,
we will first discuss on the biology of IGF-IR in an attempt
to find the role of this receptor in breast cancer and then discuss
about therapeutic strategies to target this receptor. |