Indeed, pathological remodelling of white adipose tissue and increased levels of fat-specific cytokines (mainly leptin), as a consequence of the obesity condition, have been associated with several hallmarks of breast cancer, such as sustained proliferative signaling, cellular energetics, inflammation, angiogenesis, activating invasion and metastasis.
These results suggest that leptin contributes to breast cancer progression through the transcriptional upregulation of leptin via the MAPK pathway.[BMB Reports 2019; 52(6): 385-390].
In this study, we utilized the breast cancer cell lines MCF7 and MDA-MB-231 to determine the effect of leptin on FAK and Src kinases activation, cell migration, metalloprotease secretion, and invasion.
Adiponectin +276G/T and leptin-2548G/A showed a significant increased risk for breast cancer even after adjusting for confounding variables like present age, age at menarche, age at first child birth and age at menopause.
It was determined that leptin increases the proliferation of the three breast cancer cell lines and tamoxifen is able to exert an antiproliferative effect on them, however, it was identified that the ability of tamoxifen to decrease the proliferation of cancer cells is diminished in the presence of leptin, in addition to changes in the modulation of the expression of its receptor.
This study aimed to test the effects of EE on breast cancer onset and progression while considering the effect of leptin by utilizing the transgenic MMTV-PyMT model as well as several models of varied leptin signaling.
Our results revealed a significantly higher leptin level in BC patients than in healthy controls, but no association between leptin <i>G-2548A</i> polymorphism and BC susceptibility was found.
Therefore, a better knowledge of the molecular mechanisms that mediate leptin action may be helpful to understand the underlying processes which link obesity to breast cancer in post-menopausal women, as well as the possible role of leptin in the response to immunotherapy in obese patients.
A subgroup analysis of BMI identified an association between breast cancer and serum leptin levels in patients who are overweight and obese (overweight: SMD = 0.35, 95% CI = 0.13-0.57, I = 88.1%; obesity: SMD = 1.38, 95% CI = 0.64-2.12, I = 89.6%).
Breast cancer survivors showed significant improvements in metabolic risk biomarkers and insulin resistance indicators along with a non-significant leptin decrease and a significant adiponectin decrease.
Mechanistically, adipocyte-derived interleukin-6 (IL-6) and leptin may facilitate PLOD2 upregulation in breast cancer cells and promote breast cancer metastasis in tail vein metastasis assays.
In this review, we focus on recent advances that establish: (1) leptin as a risk factor for the development of breast cancer, and (2) leptin as an inducer of EMT, an event that promotes tumor progression.
The polymorphisms of leptin (LEP) and leptin receptor (LEPR) may be associated with breast cancer by regulator of adipose tissue mass and tumor cell growth.
In conclusion, LEPG2548A polymorphism has no relationship with BC susceptibility, while LEPR Q223R polymorphism could decrease BC risk in Asians, but not in overall individuals and Caucasians.