Abstract：
Neuroblastoma (NB) is the most common extracranial solid tumor in children. Interference with the polyamine biosynthesis pathway by inhibition of MYCN-activated ornithine decarboxylase (ODC) is a validated approach. The ODC inhibitor α-difluoromethylornithine (DFMO, or Eflornithine) has been FDA-approved for the treatment of trypanosomiasis and hirsutism and has advanced to clinical cancer trials including NB as well as cancer-unrelated human diseases. One key challenge of DFMO is its rapid renal clearance and the need for high and frequent drug dosing during treatment.
We performed in vivo pharmacokinetic (PK), antitumorigenic, and molecular studies with DFMO/probenecid using NB patient-derived xenografts (PDX) in mice. We used LC-MS/MS, HPLC, and immunoblotting to analyze blood, brain tissue, and PDX tumor tissue samples collected from mice.
The organic anion transport 1/3 (OAT 1/3) inhibitor probenecid reduces the renal clearance of DFMO and significantly increases the antitumor activity of DFMO in PDX of NB (P < 0.02). Excised tumors revealed that DFMO/probenecid treatment decreases polyamines putrescine and spermidine, reduces MYCN protein levels and dephosphorylates retinoblastoma (Rb) protein (p-RbSer795), suggesting DFMO/probenecid-induced cell cycle arrest.
Addition of probenecid as an adjuvant to DFMO therapy may be suitable to decrease overall dose and improve drug efficacy in vivo.
We performed in vivo pharmacokinetic (PK), antitumorigenic, and molecular studies with DFMO/probenecid using NB patient-derived xenografts (PDX) in mice. We used LC-MS/MS, HPLC, and immunoblotting to analyze blood, brain tissue, and PDX tumor tissue samples collected from mice.
The organic anion transport 1/3 (OAT 1/3) inhibitor probenecid reduces the renal clearance of DFMO and significantly increases the antitumor activity of DFMO in PDX of NB (P < 0.02). Excised tumors revealed that DFMO/probenecid treatment decreases polyamines putrescine and spermidine, reduces MYCN protein levels and dephosphorylates retinoblastoma (Rb) protein (p-RbSer795), suggesting DFMO/probenecid-induced cell cycle arrest.
Addition of probenecid as an adjuvant to DFMO therapy may be suitable to decrease overall dose and improve drug efficacy in vivo.
摘要：
神经母细胞瘤（NB）是儿童最常见的颅外实体瘤。通过抑制MYCN激活的鸟氨酸脱羧酶（ODC）干扰多胺生物合成途径是一种有效的方法。ODC抑制剂α-二氟甲基鸟氨酸(DFMO，或Eflornithine）已被FDA批准用于治疗锥虫病和多毛症，并已进入临床癌症试验，包括NB以及与癌症无关的人类疾病。DFMO的一个关键挑战是其快速的肾脏清除以及在治疗期间需要大量和频繁的药物给药。
我们进行了体内药代动力学（PK），抗肿瘤性，以及在小鼠中使用NB患者衍生的异种移植物（PDX）进行DFMO/丙磺舒的分子研究。我们使用LC-MS/MS，HPLC,免疫印迹分析血液，脑组织,和从小鼠收集的PDX肿瘤组织样品。
有机阴离子转运1/3（OAT1/3）抑制剂丙磺舒可降低DFMO的肾脏清除率，并显着增加DFMO在NBPDX中的抗肿瘤活性（P<0.02）。切除的肿瘤显示DFMO/丙磺舒治疗减少多胺腐胺和亚精胺，降低MYCN蛋白水平和去磷酸化视网膜母细胞瘤（Rb）蛋白（p-RbSer795），提示DFMO/丙磺舒诱导的细胞周期阻滞。
向DFMO治疗中添加丙磺舒作为佐剂可能适合于降低总剂量并改善体内药物功效。
我们进行了体内药代动力学（PK），抗肿瘤性，以及在小鼠中使用NB患者衍生的异种移植物（PDX）进行DFMO/丙磺舒的分子研究。我们使用LC-MS/MS，HPLC,免疫印迹分析血液，脑组织,和从小鼠收集的PDX肿瘤组织样品。
有机阴离子转运1/3（OAT1/3）抑制剂丙磺舒可降低DFMO的肾脏清除率，并显着增加DFMO在NBPDX中的抗肿瘤活性（P<0.02）。切除的肿瘤显示DFMO/丙磺舒治疗减少多胺腐胺和亚精胺，降低MYCN蛋白水平和去磷酸化视网膜母细胞瘤（Rb）蛋白（p-RbSer795），提示DFMO/丙磺舒诱导的细胞周期阻滞。
向DFMO治疗中添加丙磺舒作为佐剂可能适合于降低总剂量并改善体内药物功效。
