Department of Anatomy and Cytoneurobiology Unit, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.
Department of Human Anatomy, Medical School of Nantong University, Nantong, Jiangsu 226001, P.R. China.
Int J Oncol. 2017 Nov;51(5):1439-1448. doi: 10.3892/ijo.2017.4132. Epub 2017 Sep 22.
Gliomas are the most common primary brain tumors affecting adults. Four grades of gliomas have been identified, namely, grades I-IV. Brain lipid-binding protein (BLBP), which functions in the intracellular transport of fatty acids, is expressed in all grades of human gliomas. The glioma cells that are cultured in vitro are grouped into the BLBP-positive and BLBP-negative cell lines. In the present study, we found that C6 rat glioma cells was a distinct type of BLBP-negative cell line. Our results confirmed that in the C6 cells, the expression of exogenous BLBP increased the proliferation and percentage of cells in the S phase, in the culture medium containing 10 or 1% FBS. Moreover, exogenous BLBP was found to downregulate the tumor suppressors p21 and p16 in the 1% FBS culture medium, but only p21 in the 10% FBS culture medium. The results of the xenograft model assay showed that exogenous BLBP also stimulated tumor formation and downregulated p21 and p16. In conclusion, our study demonstrated that exogenous BLBP promoted proliferation of the C6 cells in vitro and facilitated tumor formation in vivo. Therefore, BLBP expression in glioma cells may promote cell growth by inhibiting the tumor suppressors.
神经胶质瘤是成人中最常见的原发性脑肿瘤。已确定神经胶质瘤有四级，即 I-IV 级。脑脂质结合蛋白（BLBP）在脂肪酸的细胞内运输中起作用，在所有级别的人类神经胶质瘤中均有表达。在体外培养的神经胶质瘤细胞被分为 BLBP 阳性和 BLBP 阴性细胞系。在本研究中，我们发现 C6 大鼠神经胶质瘤细胞是一种独特的 BLBP 阴性细胞系。我们的结果证实，在 C6 细胞中，外源性 BLBP 的表达增加了增殖和 S 期细胞的百分比，在含有 10%或 1% FBS 的培养基中。此外，在外源性 BLBP 存在的情况下，1% FBS 培养基中下调肿瘤抑制因子 p21 和 p16，但在 10% FBS 培养基中仅下调 p21。异种移植模型试验的结果表明，外源性 BLBP 也刺激肿瘤形成并下调 p21 和 p16。总之，我们的研究表明，外源性 BLBP 促进了 C6 细胞在体外的增殖，并促进了体内肿瘤的形成。因此，神经胶质瘤细胞中的 BLBP 表达可能通过抑制肿瘤抑制因子来促进细胞生长。
