Circumvention of platinum resistance in human ovarian carcinoma cells by modulation of phosphotydil-inositol 4-kinase activity

基于先前的数据，我们确定了TNF α对DDP对裸鼠2008肿瘤异种移植物的治疗指数的影响。单独TNF α不改变2008异种移植物的体内生长。低剂量DDP（7 mg/kg）可使肿瘤生长轻微但显著减少。TNF α和DDP的组合导致肿瘤生长的进一步减少，其程度与常规剂量（RD）DDP（15 mg/kg）相同。TNF α与LD DDP联合应用可延长肿瘤细胞的生存期，而LD DDP或RD DDP则不能延长肿瘤细胞的生存期。因此，TNF α具有增强DDP对卵巢癌细胞的体内细胞毒性而不改变DDP的全身毒性的潜力。TPA消耗PKC增强人卵巢癌2008细胞对DDP、卡铂和（-）-（R）-2-氨甲基吡咯烷（1，1-环丁烷二羧酸）-铂（II）（DWA）的敏感性。TPA增强了DDP抗性2008/C13*5.25（C13）亚系对三种药物中的每一种的敏感性， ...更多信息 与2008年的细胞相同。由于PKCalpha是这些细胞中对TPA有反应的唯一同种型，因此这些结果表明铂敏感性可由PKCalpha调节。此外，TPA使DDP和DWA在C13细胞中的蓄积增加了70%，但在2008细胞中没有增加。TPA使2008细胞中的细胞谷胱甘肽含量降低了30%，使C13细胞中的细胞谷胱甘肽含量降低了41%。它没有改变CdCl 2的敏感性，在这两个细胞系。这些结果表明，TPA.Orobol（一种有效的磷脂酰肌醇4-激酶（PI 4K）抑制剂）的多因素致敏作用（Umezawa等人，J.Antibiotics 1990）使人卵巢癌2008细胞中对顺铂（DDP）的敏感性提高了2.1倍。致敏性取决于细胞制备和药物处理之间的滞后时间（T），并且在细胞制备后48小时（T48）最大。在细胞周期的G2+M期的细胞群体在T48中比在任何其他时间多4倍。T48中的PI 4K活性响应于用orobol处理而增加9倍。Orobol对DDP抗性亚系也产生2倍的致敏作用。因此，我们得出结论，orobol确实通过orobol敏感途径以细胞周期依赖性方式增加DDP敏感性，可能涉及PI 4K活性，并且该信号转导途径在DDP耐药细胞中也是有效的。少

Based on the previous data we have determined the effect of TNFalpha on the therapeutic index of DDP against 2008 tumor xenografts in nude mice. TNFalpha alone did not alter the in vivo growth of 2008 xenografts. Low-dose DDP(7mg/kg) caused a slight but significant reduction in tumor growth. The combination of TNFalpha and DDP resulted in further reduction in tumor growth to the same degree as seen in regular-dose (RD) DDP (15mg/kg). The combination of TNFalpha and LD DDP prolonged survival of the, wherease LD DDP or RD DDP did not do so. Hence, TNFalpha has the potential to enhance the in vivo cytotoxicity of DDP to ovarian carcinoma cells without altering systemic toxicity of DDP.Depletion of PKC by TPA enhanced the sensitivity of human ovarian carcinoma 2008 cells to DDP, carboplatin, and (-)-(R)-2-aminomethylpyrrolidine (1, 1-cyclobutanedicarboxylato)-platinum(II) (DWA). TPA enhanced the sensitivity of the DDP-resistant 2008/C13*5.25 (C13) subline to each of the three drugs to the … More same extent as for the 2008 cells. Since PKCalpha is the only isotype responsive to TPA in these cells, these results suggest that platinum sensitivity can be modulated by PKCalpha. Furthermore, TPA increased accumulation of DDP and DWA in C13 cells by 70 % but not in 2008 cells. TPA decreased cellular glutathione content by 30 % in 2008 cells and 41 % in C13 cells. It did not alter CdCl2 sensitivity in both of these cell lines. These result indicate the maltifactorial sensitization effect of TPA.Orobol, a potent phosphatidylinositol 4-kinase (PI4K) inhibitor (Umezawa et al. J.Antibiotics 1990), enhanced sensitivity to cisplatin(DDP) in human ovarian carcinoma 2008 cells by a factor of 2.1-fold. Sensitization depends on the lag-time (T) between cell preparation and drug treatment and was maximum 48 hr after cell preparation (T48). The cell population at the G2+M phase of the cell cycle was 4-fold more in T48 than in any other time. PI4K activity in T48 was incresed in response to treatment with orobol by 9-fold. Orobol also produced 2-fold sensitization in DDP-resistant subline. Thus we concluded that orobol did increase the DDP sensitivity in cell-cycle dependent manner via orobol-sensitive pathway, possibly involving PI4K activity and that this signal transduction pathway is also operative in DDP-resistant cells. Less