Objective: To investigate the mechanism of nucleolin (NCL) involved in lymphoma proliferation by regulating thymidine kinase 1 (TK1).
Methods: Twenty-three patients with diffuse large B-cell lymphoma (DLBCL) were selected and divided into initial treatment group (14 cases) and relapsed/refractory group (9 cases). Serum TK1 and C23 protein in peripheral blood mononuclear cells were detected. Cell models of CA46-NCL-KD (CA46-NCL-knockdown) and CA46-NCL-KNC (CA46-NCL-knockdown negative control) were established by lentivirus vector mediated transfection in Burkitt lymphoma cell line CA46. The half maximal inhibitory concentration (IC50) of CA46-NCL-KD, CA46-NCL-KNC, and CA46 to adriamycin were detected by cell proliferation assay (MTS). The expression of NCL mRNA and protein in CA46-NCL-KD and CA46-NCL-KNC cells were dectected by Q-PCR and Western blot, respectively. The cell cycle of CA46-NCL-KD, CA46-NCL-KNC, and CA46 cells were detected by flow cytometry. The expression of TK1 protein in CA46-NCL-KD and CA46-NCL-KNC cells was detected by an enhanced chemiluminescence (ECL) dot blot assay.
Results: The level of serum TK1 in the initial treatment group was 0.43(0-30-1.01) pmol/L, which was lower than 10.56(2.19-14.99) pmol/L in the relapsed/refractory group (P<0-01), and the relative expression level of NCL protein in peripheral blood was also significantly lower. The IC50 of CA46-C23-KD cells to adriamycin was (0.147±0.02) μg/ml, which was significantly lower than (0.301±0.04) μg/ml of CA46-C23-KNC cells and (0.338±0.05) μg/ml of CA46 cells (P<0.05). Compared with CA46-NCL-KNC cells, the expression of NCL mRNA and protein, TK1 protein decreased in CA46-NCL-KD cells, and the proportion of S phase and G2/M phase also decreased, while G0/G1 phase increased in cell cycle.
Conclusion: The increased expression of NCL in DLBCL and CA46 cells indicates low sensitivity to drug. NCL may participate in regulation of lymphoma proliferation by affecting TK1 expression, thereby affecting the drug sensitivity.
题目: 核仁素通过调控胸苷激酶1影响淋巴瘤增殖的研究.
目的: 探讨核仁素通过胸苷激酶1（TK1）参与淋巴瘤增殖调控的机制.
方法: 选取弥漫性大B细胞淋巴瘤患者23例，纳入初治组14例，复发/难治组9例，检测患者血清TK1以及外周血单个核细胞中C23蛋白。以Burkitt淋巴瘤细胞株CA46为研究对象，通过慢病毒介导的转染方法，获得RNAi核仁素基因表达下调的细胞模型CA46-NCL-KD及阴性对照组细胞模型CA46-NCL-KNC；采用细胞增殖法（MTS法）分别检测CA46-NCL-KD、CA46-NCL-KNC和CA46对阿霉素的增殖半数抑制率（IC50）。通过Q-PCR和Western blot分别检测CA46-NCL-KD、CA46-NCL-KNC细胞NCL mRNA和蛋白表达水平，用流式细胞术对CA46-NCL-KD、CA46-NCL-KNC和CA46细胞进行细胞周期检测，用酶免疫点印记化学发光法分析CA46-NCL-KD、CA46-NCL-KNC细胞TK1蛋白的表达情况.
结果: 初治组患者血清TK1水平为0.43(0-30-1.01)pmol/L，低于复发/难治组患者的10.56(2.19-14.99)pmol/L（P<0.01），且初治组患者外周血单个核细胞NCL蛋白相对表达量明显低于复发/难治组。CA46-NCL-KD对阿霉素的IC50为(0.147±0.02)μg/ml，明显低于CA46-NCL-KNC的(0.301±0.04)μg/ml以及CA46的(0.338±0.05)μg/ml（P<0.05）；与CA46-NCL-KNC相比，CA46-NCL-KD中NCL mRNA和蛋白水平表达下降，细胞周期中的G0/G1期比例升高，S期及G2/M期比例下降，TK1蛋白表达下降.
结论: 在弥漫大B细胞淋巴瘤细胞以及淋巴瘤细胞株CA46细胞中NCL表达升高，提示细胞对药物敏感度降低，NCL可能通过影响TK1表达参与淋巴瘤细胞增殖的调控，从而影响淋巴瘤细胞对药物的敏感性.
Keywords: CA46 cells; cell cycle; lymphoma; nucleolin; thymidine kinase 1.