Mast cells promote melanoma colonization of lungs

Abstract

Mast cells have been implicated in malignant processes, mainly through clinical correlative studies and by experiments performed using animals lacking mast cells due to defective c-kit signaling. However, mast cell-deficient mouse models based on c-kit defects have recently been questioned for their relevance. Here we addressed the effect of mast cells in a tumor setting by using transgenic Mcpt5-Cre+ R-DTA+ mice, in which the deficiency of mast cells is independent of c-kit defects. Melanoma cells (B16.F10) were administered either subcutaneously or intravenously into Mcpt5-Cre+ R-DTA+ mice or Mcpt5-Cre− R-DTA+ littermate controls, followed by the assessment of formed tumors. In the subcutaneous model, mast cells were abundant in the tumor stroma of control mice but were absent in Mcpt5-Cre+ R-DTA+ mice. However, the absence of mast cells did not affect tumor size. In contrast, after intravenous administration of B16.F10 cells, melanoma colonization of the lungs was markedly reduced in Mcpt5-Cre+ R-DTA+ vs. Mcpt5-Cre− R-DTA+ animals. Decreased melanoma colonization of the lungs in Mcpt5-Cre+ R-DTA+ animals was accompanied by increased inflammatory cell recruitment into the bronchoalveolar lavage fluid, suggesting that mast cells suppress inflammation in this setting. Further, qPCR analysis revealed significant alterations in the expression of Twist and E-cadherin in lungs of Mcpt5-Cre+ R-DTA+ vs. control Mcpt5-Cre− R-DTA+ animals, suggesting an impact of mast cells on epithelial-mesenchymal transition. In conclusion, this study reveals that mast cells promote melanoma colonization of the lung.

Acidic pH is essential for maintaining mast cell secretory granule homeostasis

“…qPCR was performed as described previously. 35 The RNA isolation kit was from Macherey-Nagel (Düren, Germany), and the cDNA synthesis kit was from Bio-rad (Solna, Sweden). SYBR GreenER SuperMix from Invitrogen (Carlsbad, CA, USA) was used.…”

Protective role of mouse mast cell tryptase Mcpt6 in melanoma

“…To gain more mechanistic insight into the role of MCs in melanoma, we previously examined melanoma progression in wild‐type (WT) mice versus mice that lacked connective tissue‐type MCs altogether (Dudeck et al, ), using a model of melanoma colonization to the lung. In that study, we found that MCs had an overall detrimental impact (Öhrvik et al, ) and to dissect the underlying mechanism we assessed mice lacking all of the MC proteases in the same model. Strikingly, we found that mice with global MC protease deficiency, contrary to the mice lacking MCs altogether, developed larger tumors than did WT mice (Grujic et al, ).…”

Mast Cells as an Indicator and Prognostic Marker in Molecular Subtypes of Breast Cancer

“…Studies have shown that mast cells accumulate in a variety of malignant tumors, such as melanoma, Hodgkin's lymphoma and chronic lymphocytic leukemia, pancreatic, prostate and esophageal cancer (5). Some reports have shown that the high number of MCs is associated with a good prognosis (6), while others have noticed their association with poor prognosis and distant metastasis (7)(8)(9). Some reports suggest that mast cells play a promoting role in the occurrence and development of malignant tumors (10,11).…”