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Chemical-Induced Skin Carcinogenesis Model Using Dimethylbenz[a]Anthracene and 12-O-Tetradecanoyl Phorbol-13-Acetate DMBA-TPA
Published on: December 19, 2019
Slit2 promotes tumor growth and invasion in chemically induced skin carcinogenesis
Cuiling Qi1, Haimei Lan2, Jie Ye1
1Vascular Biology Research Institute, Guangdong Pharmaceutical University, Guangzhou, China.
Abstract:
Slit, a neuronal guidance cue, binds to Roundabout (Robo) receptors to modulate neuronal, leukocytic, and endothelial migration. Slit has been reported to have an important effect on tumor growth and metastasis. In the current study, we evaluated the role of Slit2 in skin tumor growth and invasion in mice using a two-step chemical carcinogenesis protocol. We found that Slit2 expression correlated with the loss of basement membrane in the samples of human skin squamous cell carcinoma at different stages of disease progression. Slit2-Tg mice developed significantly more skin tumors than wild-type mice. Furthermore, the skin tumors that occurred in Slit2-Tg mice were significantly larger than those in the wild-type mice 10 weeks after 7,12-dimethylbenz[a]anthracene initiation until the end of the experiment. We also found that pathological development of the wild-type mice was delayed compared with that of Slit2-Tg mice. To further investigate the mechanism of increasing tumors in Slit2-Tg mice, we analyzed the expression of 5-bromo-2'-deoxyuridine (BrdU) in mouse skin lesions and found that the number of BrdU-positive cells and microvessel density in skin lesions were significantly higher in Slit2-Tg mice than in wild-type mice. Histological staining of PAS and type IV collagen and the colocalization of Slit2 and type IV collagen demonstrated varying degrees of loss of the basement membrane in the skin lesions from Slit2-Tg mice that were at the stage of carcinoma in situ. However, the basement membrane was well defined in the wild-type mice. In addition, MMP2, but not MMP9, was upregulated in the skin tissue of Slit2-Tg mice. Interruption of Slit2-Robo1 signaling by the antibody R5 significantly repressed the invasive capability of the squamous cell carcinoma cell line A431. Taken together, our findings reveal that Slit2 promotes DMBA/TPA-induced skin tumorigenesis by increasing cell proliferation, microvessel density, and invasive behavior of cutaneous squamous cell carcinoma, along with loss of basement membrane, by upregulation of MMP2 expression.
Insights
Slit2 protein accelerates skin tumor development and invasion in mice by increasing cell proliferation, blood vessel formation, and matrix metalloproteinase-2 (MMP2) expression, leading to basement membrane degradation.
Area of Science:
- Oncology
- Cell Biology
- Dermatology
Background:
- Slit proteins, acting as guidance cues, regulate cell migration and are implicated in tumor progression.
- The role of Slit2 in skin tumorigenesis and invasion requires further elucidation.
Purpose of the Study:
- To investigate the function of Slit2 in chemical-induced skin tumor growth and invasion in mice.
- To elucidate the underlying molecular mechanisms by which Slit2 influences skin carcinogenesis.
Main Methods:
- A two-step chemical carcinogenesis protocol in wild-type and Slit2-transgenic (Slit2-Tg) mice.
- Analysis of tumor incidence, size, proliferation (BrdU incorporation), microvessel density, basement membrane integrity (PAS and type IV collagen staining), and matrix metalloproteinase (MMP) expression (MMP2 and MMP9).
- In vitro assessment of squamous cell carcinoma cell invasion upon interruption of Slit2-Robo1 signaling.
Main Results:
- Slit2 expression correlated with basement membrane loss in human skin squamous cell carcinoma.
- Slit2-Tg mice exhibited increased skin tumor development, larger tumor size, and accelerated pathological progression compared to wild-type mice.
- Elevated cell proliferation, microvessel density, and upregulation of MMP2 were observed in Slit2-Tg mice, alongside basement membrane degradation.
Conclusions:
- Slit2 significantly promotes 7,12-dimethylbenz[a]anthracene/12-O-tetradecanoylphorbol-13-acetate (DMBA/TPA)-induced skin tumorigenesis.
- Slit2 enhances tumor growth and invasion by increasing cell proliferation, angiogenesis, and MMP2 expression, which contributes to basement membrane breakdown.
- Targeting Slit2-Robo1 signaling may represent a therapeutic strategy for cutaneous squamous cell carcinoma.
