Liu J, Zhou Q, Wu C P, Xu Y W, Liu W L, Zhao H F, Li W P
Department of Neurosurgery/Neuro-oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
Department of Neurosurgery and Shenzhen Key Laboratory of Neurosurgery, Shenzhen University 1st Affiliated Hospital, Shenzhen Second People's Hospital, Shenzhen, China.
Histol Histopathol. 2018 Sep;33(9):987-994. doi: 10.14670/HH-11-995. Epub 2018 Apr 26.
Sphingosine kinases (SPHKs), the Ki-67 index and tumor-associated macrophages (TAMs) are associated with diverse human malignancies, including glioma. SPHK2, a subtype of SPHKs, has not been assessed in glioma or correlated with the Ki-67 index or TAM infiltration. We tested the hypothesis that expression of SPHK2 correlates with the Ki-67 index and TAM infiltration in patients with glioma.
Western blot analysis was performed on protein lysates prepared from human astrocyte (HA) and glioma cell lines. Immunofluorescence was used to determine the subcellular location of SPHK2 protein in glioma cells. Next, immunohistochemistry was employed to analyze the correlations among SPHK2, Ki-67, CD68, and CD206 in 11 non-neoplastic brain tissues and 60 glioma tissues. All slides were evaluated under ×400 magnification, and the ratio of positively stained cells to the total number of cells was calculated for analysis.
SPHK2, CD68 and CD206 were all increased in glioma tissues compared to non-neoplastic brain tissues, but there were no differences between WHO grades of glioma. Ki-67 was highest in WHO grade IV tumors and lowest in non-neoplastic brain tissues, and all between-group differences were statistically significant. Moreover, SPHK2 expression was positively correlated with the Ki-67, CD68 and CD206 indexes. Finally, the CD68 and CD206 indexes were both associated with the Ki-67 index.
SPHK2 protein expression, the Ki-67 index and TAM infiltration in human glioma tissue were reported in this study for the first time. SPHK2 was positively associated with TAM infiltration and glioma proliferation. Mechanistically, SPHK2 may promote glioma growth by stimulating TAMs to polarize M2-type macrophages.
鞘氨醇激酶（SPHKs）、Ki-67指数和肿瘤相关巨噬细胞（TAMs）与包括胶质瘤在内的多种人类恶性肿瘤相关。SPHKs的一种亚型SPHK2，尚未在胶质瘤中进行评估，也未与Ki-67指数或TAM浸润相关联。我们检验了SPHK2表达与胶质瘤患者的Ki-67指数和TAM浸润相关的假设。
对从人星形胶质细胞（HA）和胶质瘤细胞系制备的蛋白质裂解物进行蛋白质印迹分析。免疫荧光用于确定SPHK2蛋白在胶质瘤细胞中的亚细胞定位。接下来，采用免疫组织化学分析11例非肿瘤性脑组织和60例胶质瘤组织中SPHK2、Ki-67、CD68和CD206之间的相关性。所有切片在×400倍放大倍数下进行评估，并计算阳性染色细胞与细胞总数的比例进行分析。
与非肿瘤性脑组织相比，胶质瘤组织中SPHK2、CD68和CD206均升高，但不同WHO分级的胶质瘤之间无差异。Ki-67在WHO IV级肿瘤中最高，在非肿瘤性脑组织中最低，且所有组间差异均具有统计学意义。此外，SPHK2表达与Ki-67、CD68和CD206指数呈正相关。最后，CD68和CD206指数均与Ki-67指数相关。
本研究首次报道了人胶质瘤组织中SPHK2蛋白表达、Ki-67指数和TAM浸润情况。SPHK2与TAM浸润和胶质瘤增殖呈正相关。从机制上讲，SPHK2可能通过刺激TAMs极化M2型巨噬细胞来促进胶质瘤生长。
