• Biomolecules & Therapeutics
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• v.18 no.4
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• pp.363-374
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• 2010

Growing evidence suggests a prominent role for leptin in human cancer progression. The intricate pattern of leptin cross-talk with other associated signaling pathways is a critical area of research that will ultimately contribute to comprehending the role of leptin in cancer progression. This review summarizes a portion of the current understanding of leptin signaling, with a critical focus on its contribution to tumor cell invasion and metastasis. Five topics are addressed in this review: (1) Leptin receptor, (2) Leptin signaling, (3) Leptin and cancer, and (4) Leptin and tumor invasion. Due to the complex cellular effects of leptin, a more precise understanding of leptin signaling pathways must still be elucidated. Leptin is clearly a major factor for stimulating tumor progression through a complex spectrum of interplay and cross-talk among various signaling molecules. An understanding of the role of leptin in invasion and metastasis will provide valuable information for establishing strategies to modulate leptin signaling, which should be a high priority for the development of anti-cancer therapeutics.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.2
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• pp.91-97
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• 2000

The purpose of the present study was to determine the preventive effects of combined interventional trial of fish oil treatment and exercise training on insulin resistance of skeletal muscle in high-fat fed rats. Male Wistar rats were randomly divided into chow diet (CD), high-fat diet (HF), high-fat diet with fish oil (FO), high-fat diet with exercise training (EX), and FO+EX groups. The rats in control group were fed chow diet containing, as percents of calories, 58.9% carbohydrate, 12.4% fat, and 28.7% protein. High-fat diet provided 32% energy as lard, 18% as corn oil, 27% as carbohydrate and 23% as casein. The fish oil diet had the same composition as the high fat diet except that 100 g menhaden oil was substituted for corn oil. Insulin sensitivity was assessed by in vitro glucose transport in the soleus muscle after diet treatment and treadmill running for 4 weeks. While the FO or EX only partially prevented insulin resistance on glucose transport and visceral obesity induced by high-fat diet, these interventions completely corrected hyperinsulinemia and hyperglycemia from the high-fat diet. The rats in the FO+EX showed normalized insulin action on glucose transport, plasma chemicals and visceral fat mass. Insulin-mediated glucose transport was negatively associated with total visceral fat mass (r=－0.734; p＜0.000), plasma triglyceride (r=－0.403; p＜0.05) and lepin (r=－0.583; p＜0.001) concentrations with significance. Multiple stepwise regression analysis showed that only total visceral fat mass was independently associated with insulin-mediated glucose transport (r=－0.668; p＜0.000). In conclusion, combined interventional trial of FO+EX recovered insulin resistance on glucose transport of skeletal muscle induced by high-fat diet. Visceral fat mass might be more important factor than plasma TG and leptin to induce insulin resistance on glucose transport of skeletal muscle in high-fat fed rats.