Abstract 2985: Interaction between the malignant melanoma cell of the primary lesion and the metastatic lesion

Abstract

Abstract Introduction: The prognosis of patients with malignant melanoma is extremely poor because of the frequent metastasis. We have occasionally experienced the clinical cases that malignant melanoma patients rapidly developed distant metastases after the surgical resection of primary cancer lesion. These cases suggested that a primary tumor may control a metastatic tumor. We hypothesized that primary melanoma cells might produce a factor(s) which regulate the progression of metastatic melanoma cells. Then we investigated the growth and invasion interaction between primary malignant melanoma cells and high metastatic melanoma cells. Materials and methods: We used two malignant melanoma cell lines, B16 as a parent primary melanoma cell line and a selected daughter cell line B16/BL6 with high metastatic ability. We investigated the invasive interaction between the parent B16 cells and daughter B16/BL6 cells in vitro. The conditioned medium from B16 cells and B16/BL6 cells was added to B16 cells or B16/BL6 cells. Then we examined the effect of these conditioned medium on the motility and proliferation of melanoma cells by MTT assay or invasion assay at 24 hours and 72 hours after the addiction of the conditioned medium. Results:The conditioned medium from B16 cells significantly (p=0.02) suppressed the invasion ability of B16/BL6 cells at 24 hours after the addiction of the conditioned medium. In contrast, the invasion ability of B16 cells were not affected by the conditioned medium from B16/BL6 cells at 24 hours. Each conditioned medium did not affect on the proliferation of both melanoma cell lines. On the other hand, at 72 hours after the addiction of the conditioned medium from B16 cells significantly (p=0.000003) suppressed the growth of B16/BL6 cells. Conclusion: Primary melanoma cells might down-regulate the progression of metastatic melanoma cells by a soluble factor(s). Citation Format: Takaharu Hatano, HIsashi Motomura, Heishiro Fujikawa, Masakazu Yashiro, Kishu Kitayama. Interaction between the malignant melanoma cell of the primary lesion and the metastatic lesion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2985. doi:10.1158/1538-7445.AM2017-2985