0000000000116106
AUTHOR
Stanislaw Sulkowski
Functional analysis of the -2548G/A leptin gene polymorphism in breast cancer cells
Leptin is overexpressed in human breast tumors and is produced by breast cancer cells in response to obesity-related stimuli. The leptin promoter polymorphism Lep-2548G/A can be associated with increased leptin secretion by adipocytes and elevated cancer risk. However, molecular mechanisms underlying the link between Lep-2548G/A and breast cancer have never been addressed. Lep-2548G/A is proximal to a binding site for the transcriptional factor Sp1. Furthermore nucleolin, a transcriptional repressor, can bind Sp1 or its consensus site. Consequently, we focused on the impact of Lep-2548G/A on Sp1- and nucleolin-dependent leptin transcription in breast cancer cells. The Lep-2548G/A was identi…
Expression of the obesity hormone leptin and its receptor correlates with hypoxia-inducible factor-1 alpha in human colorectal cancer.
Background: The obesity hormone, leptin, has been found to play a role in development and proliferation of normal and malignant tissues. Leptin activity is mediated through the leptin receptor (ObR) that is often expressed in different human cancer cells. Previously, we found that the expression of leptin and ObR can be stimulated by hypoxia-mimetic agents. The aim of this study was to analyze the abundance of and relationships among leptin, ObR and hypoxia-inducible factor-1α (HIF-1α, transcriptional regulator) in human colorectal cancer. Materials and methods: We investigated the expression of leptin, ObR and HIF-1 a in colorectal cancer specimens from 135 patients who underwent curative …
Increased expression of leptin and the leptin receptor as a marker of breast cancer progression: possible role of obesity-related stimuli.
Abstract Purpose: Recent in vitro studies suggested that the autocrine leptin loop might contribute to breast cancer development by enhancing cell growth and survival. To evaluate whether the leptin system could become a target in breast cancer therapy, we examined the expression of leptin and its receptor (ObR) in primary and metastatic breast cancer and noncancer mammary epithelium. We also studied whether the expression of leptin/ObR in breast cancer can be induced by obesity-related stimuli, such as elevated levels of insulin, insulin-like growth factor-I (IGF-I), estradiol, or hypoxic conditions. Experimental Design: The expression of leptin and ObR was examined by immunohistochemistry…