Up- and down-regulation of granulocyte/macrophage-colony stimulating factor activity in murine skin increase susceptibility to skin carcinogenesis by independent mechanisms

• Published in: Cancer research (Chicago, Ill.) Vol. 61; no. 5; pp. 2311 - 2319
• Main Authors: MANN, Amrit, BREUHAHN, Kai, SCHIRMACHER, Peter, WILHELMI, Arnd, BEYER, Carsten, ROSENAU, Andrea, ÖZBEK, Suat, ROSE-JOHN, Stefan, BLESSING, Manfred
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 01.03.2001
• Subjects: 9,10-Dimethyl-1,2-benzanthracene; Animals; Biological and medical sciences; Carcinogens; Cell physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Down-Regulation; Fundamental and applied biological sciences. Psychology; Granulocyte-Macrophage Colony-Stimulating Factor - antagonists & inhibitors; Granulocyte-Macrophage Colony-Stimulating Factor - biosynthesis; Granulocyte-Macrophage Colony-Stimulating Factor - genetics; Granulocyte-Macrophage Colony-Stimulating Factor - physiology; Keratin-10; Keratins - genetics; Melanoma, Experimental - genetics; Melanoma, Experimental - pathology; Mice; Mice, Transgenic; Molecular and cellular biology; Neoplasm Transplantation; Phenotype; Skin - metabolism; Skin Neoplasms - chemically induced; Skin Neoplasms - etiology; Skin Neoplasms - genetics; Skin Neoplasms - metabolism; Skin Physiological Phenomena - drug effects; Skin Physiological Phenomena - genetics; Tetradecanoylphorbol Acetate; Transgenes; Up-Regulation; Cell proliferation; Gene product; Rodentia; Cytokine; Transgenic animal; Gene overexpression; Epidermis; Malignant tumor; Gene expression; Carcinogenesis; Vertebrata; Mammalia; Sensitivity resistance; Mouse; Cell death; Animal; Skin; Antagonist; Mechanism of action; Tumor promotion; Granulocyte macrophage colony stimulating factor; Apoptosis
• ISSN: 0008-5472; 1538-7445

The role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in tumorigenesis is complex. On the one hand, GM-CSF can promote tumor cell growth, survival, and even metastasis. On the other hand, it can stimulate tumor cell rejection. In skin, it is early expressed after topic application of tumor-promoting agents and therefore may be responsible for changes that correlate with skin tumor promotion (e.g., epidermal hyperproliferation and inflammation). To analyze GM-CSF function in skin tumorigenesis, we generated transgenic mice epidermally overexpressing either GM-CSF or a GM-CSF antagonist. Both types of transgenic mice exhibited significantly increased numbers of benign tumors in a two-step skin carcinogenesis experiment using 7',12'-dimethylbenz[a]anthracene (DMBA) as initiator and 12-O-tetradecanoylphorbol-CSF displayed a significantly elevated carcinoma burden following a single-step carcinogenesis protocol consisting of tumor initiation only. Therefore, endogenous promotion is responsible for elevated tumor development in GM-CSF-overexpressing mice. In antagonist transgenic animals, an increased tumorigenicity of modified B16 tumor cells after cutaneous transplantation as compared with nontransgenic or GM-CSF transgenic mice was observed. Thus, the antitumor activity leading to the repression of tumor cell growth in control mice is GM-CSF dependent and is compromised in mice expressing the antagonist. We suggest that both, up-regulation and down-regulation of GM-CSF activity in skin, increase the incidence and growth of tumors via two independent mechanisms: endogenous tumor promotion in the case of increased GM-CSF activity and compromised tumor cell rejection in the case of decreased GM-CSF activity.