The features of leptin and its receptor expression in metastatic cutaneous melanoma

Leptin is a multifunctional hormone with the activity of cytokines, which regulates critical signaling pathways that can induce cell proliferation, invasion, angiogenesis and tumor growth. Leptin plays an important role in the regulation of metabolism, energy exchange, functions of the neuro-endocrine system, including the pituitary, hypothalamus, adrenals, and immune system functions. Recently, some evidences have been appeared concerning the role of leptin in induction of chronic inflammatory processes, autoimmune pathologies, type 2 diabetes and cancer. An elevated blood level of the hormone is considered as a risk factor for different neoplasm development

Objective. Analysis of the hormone leptin (Lep), the long and short isoforms of its receptor (LepR1 and LepR2) expression in blood, tumor cells and normal skin fibroblasts in the patients with metastatic cutaneous melanoma (CM) with various clinico-pathological characteristics for prognostic assessment.

Materials and methods. 15 patients with metastatic CM (10 women and 5 men, aged 22 to 67 years with body mass from normal to obese) have been studied. The expression of Lep / LepR in the patient and donor blood sera, tumor and normal skin fibroblasts were determined using enzyme-linked immunosorbent assay (ELISA) and RT PCR using total RNAs isolated from pairs of tumor samples and normal tissue.

Results. Average level of leptin in the blood of CM patients and in tumor cells exceeds the normal one. Concentration of lepin in female CM patients was higher than in male patients. The expression level of Lep and LepR1 genes (but not LepR2) in tumor cells was relatively higher than in normal skin fibroblasts of these patients, and above the level of GAPDH gene expression. In the female patients with overweight (body mass index = 25,00–29,99 kg/m2 ) there was a trend to higher concentrations of leptin in the blood in comparison of the patients with normal body mass and leptin level in the sera of male CM patients. Earlier revealed relationship between the concentration of leptin in blood and the level of expression of the long isoform of its receptor in tumor cells is confirmed.

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