Wu Chiao-En, Koay Tsin Shue, Ho Yi-Hsuan, Lovat Penny, Lunec John
1Northern Institute for Cancer Research, School of Medicine, Newcastle University, Paul O'Gorman Building, Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH UK.
2Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan.
Cancer Cell Int. 2019 Mar 7;19:53. doi: 10.1186/s12935-019-0768-3. eCollection 2019.
Emergence of resistance to molecular targeted therapy constitutes a limitation to clinical benefits in cancer treatment. Cross-resistance commonly happens with chemotherapeutic agents but might not with targeted agents.
In the current study, wild-type cell lines with druggable MAPK pathway mutations [ (WM35) or (SJSA-1)] were compared with their mutant sublines (WM35-R, SN40R2) derived by selection for resistance to MDM2/p53 binding antagonists.
The continued presence of the druggable MAPK pathway targets in the mutant ( ) WM35-R and SN40R2 cells was confirmed. Trametinib and vemurafenib were tested on the paired WM35/WM35-R and SJSA-1/SN40R2 cells and similar growth inhibitory effects on the paired cell lines was observed. However, apoptotic responses to trametinib and vemurafenib were greater in WM35 than WM35-R, evidenced by FACS analysis and caspase 3/7 activity, indicating that these MAPK inhibitors acted on the cells partially through p53-regulated pathways. SiRNA mediated p53 knockdown in WM35 replicated the same pattern of response to trametinib and vemurafenib as seen in WM35-R, confirming that p53 plays a role in trametinib and vemurafenib induced apoptosis. In contrast, these differences in apoptotic response between WM35 and WM35-R were not seen with the SJSA-1/SN40R2 cell line pair. This is likely due to p53 suppression by overexpressed MDM2 in SJSA-1.
The TP53 cells selected by resistance to MDM2 inhibitors nevertheless retained growth inhibitory but not apoptotic response to MAPK pathway inhibitors.
对分子靶向治疗产生耐药性限制了癌症治疗的临床疗效。交叉耐药在化疗药物中常见，但在靶向药物中可能不会出现。
在本研究中，将具有可靶向治疗的丝裂原活化蛋白激酶（MAPK）通路突变的野生型细胞系[（WM35）或（SJSA-1）]与其通过对MDM2/p53结合拮抗剂耐药筛选获得的突变亚系（WM35-R、SN40R2）进行比较。
证实了在突变型（）WM35-R和SN40R2细胞中存在可靶向治疗的MAPK通路靶点。在配对的WM35/WM35-R和SJSA-1/SN40R2细胞上测试了曲美替尼和维莫非尼，观察到对配对细胞系具有相似的生长抑制作用。然而，通过流式细胞术分析和半胱天冬酶3/7活性证明，WM35对曲美替尼和维莫非尼的凋亡反应大于WM35-R，表明这些MAPK抑制剂部分通过p53调节的途径作用于细胞。小干扰RNA（SiRNA）介导的WM35中p53基因敲低复制了与WM35-R中所见的对曲美替尼和维莫非尼相同的反应模式，证实p53在曲美替尼和维莫非尼诱导的凋亡中起作用。相比之下，在SJSA-1/SN40R2细胞系对中未观察到WM35和WM35-R之间凋亡反应的这些差异。这可能是由于SJSA-1中过表达的MDM2对p53的抑制作用。
通过对MDM2抑制剂耐药筛选得到的TP53细胞对MAPK通路抑制剂仍保留生长抑制作用，但无凋亡反应。
