Mouse Models to Study Leptin in Breast Cancer Stem Cells. In: Berger NA, editor. Murine Models, Energy Balance, and Cancer. Cham: Springer International Publishing; 2015. pp. 127-51. [DOI: 10.1007/978-3-319-16733-6_7]

The role of SOX family members in solid tumours and metastasis

Cancer is a heavy burden for humans across the world with high morbidity and mortality. Transcription factors including sex determining region Y (SRY)-related high-mobility group (HMG) box (SOX) proteins are thought to be involved in the regulation of specific biological processes. The deregulation of gene expression programs can lead to cancer development. Here, we review the role of the SOX family in breast cancer, prostate cancer, renal cell carcinoma, thyroid cancer, brain tumours, gastrointestinal and lung tumours as well as the entailing therapeutic implications. The SOX family consists of more than 20 members that mediate DNA binding by the HMG domain and have regulatory functions in development, cell-fate decision, and differentiation. SOX2, SOX4, SOX5, SOX8, SOX9, and SOX18 are up-regulated in different cancer types and have been found to be associated with poor prognosis, while the up-regulation of SOX11 and SOX30 appears to be favourable for the outcome in other cancer types. SOX2, SOX4, SOX5 and other SOX members are involved in tumorigenesis, e.g. SOX2 is markedly up-regulated in chemotherapy resistant cells. The SoxF family (SOX7, SOX17, SOX18) plays an important role in angio- and lymphangiogenesis, with SOX18 seemingly being an attractive target for anti-angiogenic therapy and the treatment of metastatic disease in cancer. In summary, SOX transcription factors play an important role in cancer progression, including tumorigenesis, changes in the tumour microenvironment, and metastasis. Certain SOX proteins are potential molecular markers for cancer prognosis and putative potential therapeutic targets, but further investigations are required to understand their physiological functions.

Leptin Regulation of Cancer Stem Cells in Breast and Gynecologic Cancer

It is well established that obesity increases the incidence and worsens the prognosis of women's cancer. For breast cancer, women with obesity exhibit more than a twofold increase in the odds of being diagnosed with cancer, with a greater risk of advanced stage at diagnosis, and ≤40% greater risk of recurrence and death than their normal-weight counterparts. These findings are similar in gynecologic cancers, where women who are obese with a body mass index (BMI) >40 kg/m2 have up to six times greater risk of developing endometrial cancer and a 9.2% increase in mortality with every 10% increase in BMI. Likewise, patients with obesity exhibit a twofold higher risk of premenopausal ovarian cancer, and patients who are obese with advanced stage ovarian cancer have shown a shorter time to recurrence and poorer overall survival. Obesity is accompanied by changes in expression of adipose factors that act on local tissues and systemically. Once obesity was recognized as a factor in cancer incidence and progression, the adipose cytokine (adipokine) leptin became the focus of intense investigation as a putative link, with nearly 3000 publications on the topic. Leptin has been shown to increase cell proliferation, inhibit apoptosis, promote angiogenesis, and increase therapeutic resistance. These characteristics are associated with a subset of cells in both liquid and solid tumors known as cancer stem cells (CSCs), or tumor initiating cells. We will review the literature discussing leptin's role in breast and gynecologic cancer, focusing on its role in CSCs, and consider goals for targeting future therapy in this arena to disrupt tumor initiation and progression in women's cancer.