Unidad de Bioquímica, Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubirán", Vasco de Quiroga 15, Sección XVI, Delegación Tlalpan, CP 14000, Mexico, DF, Mexico.
J Cancer Res Clin Oncol. 2013 Oct;139(10):1625-35. doi: 10.1007/s00432-013-1476-3. Epub 2013 Jul 28.
NF-κB transcription factor has been associated with cancer development and chemoresistance. We studied the signaling pathway activated by doxorubicin (DOX) leading to NF-κB activation in breast cancer cells.
NF-κB activity was evaluated by electrophoretic mobility shift in T47D, ZR75.30 and primary culture (MBCDF) from a ductal infiltrating carcinoma. Cell viability was measured by crystal violet. Western blotting was performed to check the expression and phosphorylation of IκBα Ser-32/36. c-Abl was inhibited with Imatinib or by overexpressing a dominant negative form of c-Abl (K290R).
We found a correlation between sensitivity to DOX and amplitude of NF-κB activation. In cells least sensitive to DOX, NF-κB remained activated for longer time (T47D and MBCDF). The opposite effect was observed in cells sensitive to DOX (ZR75.30). DOX did not induce IκBα degradation or Ser-32/36 phosphorylation. Instead, there were modifications in the levels of IκBα tyrosine phosphorylation, suggesting an atypical NF-κB activation. In DOX-resistant cells, Imatinib treatment reduced IκBα tyrosine phosphorylation and NF-κB activity. The Imatinib-DOX combination significantly enhanced cell death of T47D and MBCDF breast cancer cells. Overexpression of c-Abl K290R in T47D and MBCDF cells reduced basal and DOX-induced NF-κB activation as well as IκBα tyrosine phosphorylation. In c-Abl K290R cells, DOX treatment did not mimic the combination Imatinib-DOX-induced cell death.
Inhibition of c-Abl inactivated IκBα/NF-κB pathway is associated with IκBα tyrosine phosphorylation in breast cancer cells. These results also raise the potential use of a combined therapy with Imatinib and DOX for breast cancer patients.
NF-κB 转录因子与癌症的发生和化疗耐药性有关。我们研究了阿霉素（DOX）激活的信号通路，导致乳腺癌细胞中 NF-κB 的激活。
通过电泳迁移率变动评估 T47D、ZR75.30 和来自导管浸润性癌的原代培养（MBCDF）中的 NF-κB 活性。通过结晶紫测量细胞活力。通过 Western 印迹检查 IκBα Ser-32/36 的表达和磷酸化。用伊马替尼抑制 c-Abl 或过表达 c-Abl 的显性负形式（K290R）。
我们发现 DOX 敏感性与 NF-κB 激活幅度之间存在相关性。在对 DOX 最不敏感的细胞中，NF-κB 的激活时间更长（T47D 和 MBCDF）。在对 DOX 敏感的细胞中观察到相反的效果（ZR75.30）。DOX 不诱导 IκBα 降解或 Ser-32/36 磷酸化。相反，IκBα 酪氨酸磷酸化水平发生变化，提示非典型 NF-κB 激活。在 DOX 耐药细胞中，伊马替尼处理降低 IκBα 酪氨酸磷酸化和 NF-κB 活性。伊马替尼-DOX 联合显著增强 T47D 和 MBCDF 乳腺癌细胞的细胞死亡。在 T47D 和 MBCDF 细胞中过表达 c-Abl K290R 降低了基础和 DOX 诱导的 NF-κB 激活以及 IκBα 酪氨酸磷酸化。在 c-Abl K290R 细胞中，DOX 处理不能模拟伊马替尼-DOX 诱导的细胞死亡组合。
在乳腺癌细胞中，c-Abl 的抑制使 IκBα/NF-κB 途径失活与 IκBα 酪氨酸磷酸化有关。这些结果还提出了伊马替尼和 DOX 联合治疗乳腺癌患者的潜在用途。
