Radiolabeled fragmented F(ab')₂ antibodies had shown better therapeutic efficacy than radiolabeled intact antibodies in treating cancers. In this study, we investigated the differences and similarities on the mechanism and extent of cell death in Raji cells (Burkitt’s lymphoma) in response to 370 kBq of ¹³¹I-F(ab')₂-Rituximab and ¹³¹I-Rituximab up to 72 h. F(ab')₂ of Rituximab was prepared and characterized by SE-HPLC and SDS-PAGE. Fragmented and intact Rituximab were radioiodinated by Chloramine-T method. Toxicity and mechanism of cell death in Raji cells in response to ¹³¹I-F(ab')₂-Rituximab and ¹³¹I-Rituximab were studied by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), LDH (lactate dehydrogenase), trypan blue exclusion, viability, apoptotic, caspase assays and cell cycle analysis. The cytotoxicity assays showed slow death of Raji cells up to 24 h in response to both ¹³¹I-F(ab')₂-Rituximab and ¹³¹I-Rituximab. Cell cycle analysis at 30 h showed G1 arrest in Raji cells which led to its slow cell death up to 24 h. Elucidative assays to identify the molecular mechanism of death of G1arrested Raji cells showed apoptotic cell death at 40 h after treatment, which was validated by demonstrating caspase activation in arrested Raji cells. Toxicity studies and mechanism of cell death in Raji cells demonstrated comparable results when treated with equivalent doses (370 kBq) of radiolabeled antibodies indicating ¹³¹I-F(ab')₂-Rituximab as a potential radioimmunotherapeutic agent for patients with Non-Hodgkin’s lymphoma.

中文翻译：

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低剂量的131I-F（ab'）2-利妥昔单抗和131I-利妥昔单抗诱导Raji细胞（伯基特淋巴瘤）的G1逮捕和凋亡

放射性标记的片段化F（ab'）₂抗体在治疗癌症方面显示出比放射性标记的完整抗体更好的治疗效果。在这项研究中，我们调查了¹²³ I-F（ab'）_2-利妥昔单抗和¹³¹ I-利妥昔单抗的370 kBq响应长达72小时，Raji细胞（伯基特淋巴瘤）细胞死亡的机制和程度的差异和相似性。制备了利妥昔单抗的F（ab'）₂并通过SE-HPLC和SDS-PAGE表征。碎片和完整的利妥昔单抗通过氯胺-T法放射性碘标记。¹³¹ I-F（ab'）_2-利妥昔单抗和¹³¹对Raji细胞的毒性和细胞死亡机制通过MTT（3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四唑溴化物），LDH（乳酸脱氢酶），台盼蓝排除法，存活率，凋亡，胱天蛋白酶试验和细胞周期分析研究了I-利妥昔单抗。细胞毒性试验显示，对¹³¹ I-F（ab'）_2-利妥昔单抗和¹³¹ I响应时，Raji细胞的缓慢死亡长达24小时利妥昔单抗。30小时的细胞周期分析显示，G1在Raji细胞中停滞，导致其缓慢的细胞死亡长达24小时。鉴定G1阻滞的Raji细胞死亡的分子机制的阐明性试验显示，治疗后40小时凋亡细胞死亡，这通过证实被阻滞的Raji细胞中的半胱天冬酶激活而得到证实。当用等剂量（370 kBq）的放射性标记抗体治疗时，Raji细胞的毒性研究和细胞死亡机制证明了可比的结果，表明¹³¹ I-F（ab'）_2-利妥昔单抗是非霍奇金淋巴瘤患者潜在的放射免疫治疗剂。