Miyashita Azusa, Fukushima Satoshi, Nakahara Satoshi, Yamashita Junji, Tokuzumi Aki, Aoi Jun, Ichihara Asako, Kanemaru Hisashi, Jinnin Masatoshi, Ihn Hironobu
Department of Dermatology and Plastic Surgery, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, Japan.
PLoS One. 2015 Dec 7;10(12):e0144241. doi: 10.1371/journal.pone.0144241. eCollection 2015.
Recent studies have shown that immunotherapies and molecular targeted therapies are effective for advanced melanoma. Non-antigen-specific immunotherapies such as immunocheckpoint blockades have been shown to be effective in the treatment of advanced melanoma. However, the response rates remain low. To improve their efficacy, they should be combined with antigen-specific immunotherapy. Elevated expression of the transcription factor, Forkhead box M1 (FOXM1), has been reported in various human cancers, and it has been shown to have potential as a target for immunotherapy. The purpose of this study was to investigate the FOXM1 expression in human melanoma samples and cell lines, to evaluate the relationship between the FOXM1 expression and the clinical features of melanoma patients and to investigate the association between the FOXM1 and MAPK and PI3K/AKT pathways in melanoma cell lines. We conducted the quantitative reverse transcription PCR (qRT-PCR) and Western blotting analyses of melanoma cell lines, and investigated melanoma and nevus tissue samples by qRT-PCR and immunohistochemistry. We performed MEK siRNA and PI3K/AKT inhibitor studies and FOXM1 siRNA studies in melanoma cell lines. We found that FOXM1 was expressed in all of the melanoma cell lines, and was expressed in 49% of primary melanomas, 67% of metastatic melanomas and 10% of nevi by performing immunohistochemical staining. Metastatic melanoma samples exhibited significantly higher mRNA levels of FOXM1 (p = 0.004). Primary melanomas thicker than 2 mm were also more likely to express FOXM1. Patients whose primary melanoma expressed FOXM1 had a significantly poorer overall survival compared to patients without FOXM1 expression (p = 0.024). Downregulation of FOXM1 by siRNA significantly inhibited the proliferation of melanoma cells, and blockade of the MAPK and PI3K/AKT pathways decreased the FOXM1 expression in melanoma cell lines. In conclusion, FOXM1 is considered to be a new therapeutic target for melanoma.
近期研究表明，免疫疗法和分子靶向疗法对晚期黑色素瘤有效。非抗原特异性免疫疗法，如免疫检查点阻断，已被证明在晚期黑色素瘤治疗中有效。然而，应答率仍然较低。为提高其疗效，应将它们与抗原特异性免疫疗法联合使用。据报道，转录因子叉头框M1（FOXM1）在多种人类癌症中表达升高，并且已显示出作为免疫治疗靶点的潜力。本研究的目的是调查FOXM1在人类黑色素瘤样本和细胞系中的表达，评估FOXM1表达与黑色素瘤患者临床特征之间的关系，并研究黑色素瘤细胞系中FOXM1与MAPK和PI3K/AKT通路之间的关联。我们对黑色素瘤细胞系进行了定量逆转录PCR（qRT-PCR）和蛋白质印迹分析，并通过qRT-PCR和免疫组织化学研究了黑色素瘤和痣组织样本。我们在黑色素瘤细胞系中进行了MEK siRNA和PI3K/AKT抑制剂研究以及FOXM1 siRNA研究。我们发现，通过免疫组织化学染色，FOXM1在所有黑色素瘤细胞系中均有表达，在49%的原发性黑色素瘤、67%的转移性黑色素瘤和10%的痣中表达。转移性黑色素瘤样本中FOXM1的mRNA水平显著更高（p = 0.004）。厚度超过2 mm的原发性黑色素瘤也更有可能表达FOXM1。与未表达FOXM
