Leptin Enhances Melanoma Tumor Growth by Increasing Endothelial Progenitor Cells

Background: Epidemiological studies propose that obesity increases the risk of several cancers, including melanoma. Leptin is a peptide predominantly produced by adipocytes. Obesity increases the expression of leptin. On the other hand, several recent experiments have suggested that tumor growth to...

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Main Authors: Shaghaygh Haghjooy Javanmard, Mahdi Khorshidi Behzadi, Fatemehsadat Amjadi, Majid Khazaei, Hamid Zarkesh Esfahani
Format: Article
Language:fas
Published: Isfahan University of Medical Sciences 2012-03-01
Series:مجله دانشکده پزشکی اصفهان
Subjects:
Online Access:http://jims.mui.ac.ir/index.php/jims/article/view/1463
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author Shaghaygh Haghjooy Javanmard
Mahdi Khorshidi Behzadi
Fatemehsadat Amjadi
Majid Khazaei
Hamid Zarkesh Esfahani
author_facet Shaghaygh Haghjooy Javanmard
Mahdi Khorshidi Behzadi
Fatemehsadat Amjadi
Majid Khazaei
Hamid Zarkesh Esfahani
author_sort Shaghaygh Haghjooy Javanmard
collection DOAJ
description Background: Epidemiological studies propose that obesity increases the risk of several cancers, including melanoma. Leptin is a peptide predominantly produced by adipocytes. Obesity increases the expression of leptin. On the other hand, several recent experiments have suggested that tumor growth to be dependent on endothelial progenitor cells (EPCs) which are effective in generation of new blood vessels. Our objectives in the present study were to examine the effects of leptin on melanoma growth and circulating EPCs number. Methods: Melanoma tumors were induced by subcutaneous injections of 2 × 106 B16F10 melanoma cells to 32 C57BL6 mice. The mice were randomly divided into 4 groups of 8 on the 8th day. The first two groups received intraperitoneal (IP) injections of either phosphate-buffered saline (PBS) or recombinant murine leptin (1 μg/g initial body weight) twice daily. The other two groups received IP injections of either 9F8 (an anti leptin receptor antibody) or the control mouse IgG at 50 μg/mouse every 3 consecutive days. By the end of the second week, the animals were euthanized and blood samples were saved for computation with flow cytometry. The tumors were also analyzed. Findings: The EPC numbers in leptin, PBS, 9F8, and IgG groups were 222.66 ± 36.5, 133.33 ± 171, 23.33 ± 18, 132.66 ± 27.26 per ml of blood, respectively. Moreover, the corresponding values for tumor weights were 3.2 ± 0.6, 1.7 ± 0.3, 1.61 ± 0.2, 1.7 ± 0.3 g. Tumors weight and size, and circulating EPC numbers were significantly more in the leptin group than 9F8 and both control groups (P < 0.05). Conclusion: In conclusion, our observations indicated that leptin caused melanoma growth likely through increased circulating EPC numbers and consequently vasculogenesis.
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spelling doaj.art-01cf5a77a8c340abaa6e90a76ef9318c2023-09-03T01:02:59ZfasIsfahan University of Medical Sciencesمجله دانشکده پزشکی اصفهان1027-75951735-854X2012-03-0129170862Leptin Enhances Melanoma Tumor Growth by Increasing Endothelial Progenitor CellsShaghaygh Haghjooy Javanmard0Mahdi Khorshidi Behzadi1Fatemehsadat Amjadi2Majid Khazaei3Hamid Zarkesh Esfahani4Assistant Professor, Physiology Research Center and Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IranPhysiology Research Center, Isfahan University of Medical Sciences, Isfahan, IranDepartment of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IranAssociate Professor, Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IranAssociate Professor, Department of Immunology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, IranBackground: Epidemiological studies propose that obesity increases the risk of several cancers, including melanoma. Leptin is a peptide predominantly produced by adipocytes. Obesity increases the expression of leptin. On the other hand, several recent experiments have suggested that tumor growth to be dependent on endothelial progenitor cells (EPCs) which are effective in generation of new blood vessels. Our objectives in the present study were to examine the effects of leptin on melanoma growth and circulating EPCs number. Methods: Melanoma tumors were induced by subcutaneous injections of 2 × 106 B16F10 melanoma cells to 32 C57BL6 mice. The mice were randomly divided into 4 groups of 8 on the 8th day. The first two groups received intraperitoneal (IP) injections of either phosphate-buffered saline (PBS) or recombinant murine leptin (1 μg/g initial body weight) twice daily. The other two groups received IP injections of either 9F8 (an anti leptin receptor antibody) or the control mouse IgG at 50 μg/mouse every 3 consecutive days. By the end of the second week, the animals were euthanized and blood samples were saved for computation with flow cytometry. The tumors were also analyzed. Findings: The EPC numbers in leptin, PBS, 9F8, and IgG groups were 222.66 ± 36.5, 133.33 ± 171, 23.33 ± 18, 132.66 ± 27.26 per ml of blood, respectively. Moreover, the corresponding values for tumor weights were 3.2 ± 0.6, 1.7 ± 0.3, 1.61 ± 0.2, 1.7 ± 0.3 g. Tumors weight and size, and circulating EPC numbers were significantly more in the leptin group than 9F8 and both control groups (P < 0.05). Conclusion: In conclusion, our observations indicated that leptin caused melanoma growth likely through increased circulating EPC numbers and consequently vasculogenesis.http://jims.mui.ac.ir/index.php/jims/article/view/1463MelanomaLeptinEndothelial progenitor cell
spellingShingle Shaghaygh Haghjooy Javanmard
Mahdi Khorshidi Behzadi
Fatemehsadat Amjadi
Majid Khazaei
Hamid Zarkesh Esfahani
Leptin Enhances Melanoma Tumor Growth by Increasing Endothelial Progenitor Cells
مجله دانشکده پزشکی اصفهان
Melanoma
Leptin
Endothelial progenitor cell
title Leptin Enhances Melanoma Tumor Growth by Increasing Endothelial Progenitor Cells
title_full Leptin Enhances Melanoma Tumor Growth by Increasing Endothelial Progenitor Cells
title_fullStr Leptin Enhances Melanoma Tumor Growth by Increasing Endothelial Progenitor Cells
title_full_unstemmed Leptin Enhances Melanoma Tumor Growth by Increasing Endothelial Progenitor Cells
title_short Leptin Enhances Melanoma Tumor Growth by Increasing Endothelial Progenitor Cells
title_sort leptin enhances melanoma tumor growth by increasing endothelial progenitor cells
topic Melanoma
Leptin
Endothelial progenitor cell
url http://jims.mui.ac.ir/index.php/jims/article/view/1463
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