To investigate the regulatory effect of everolimus on biological behaviors of rdafitinib-resistant bladder cancer cells and the underlying mechanism. An erdafitinib-resistant RT-112-RS cell model was established by continuous induction of RT-112 cells with erdafitinib at the optimized concentration (5 μmol/L) for 16 weeks. The resistant cells were treated with PDGF-BB alone or in combination with 0.01, 0.1, or 1 μmol/L everolimus, and the cytotoxicity (IC50) of everolimus was determined with CCK-8 assay. The changes in cell migration and invasion were evaluated using scratch wound healing assay and Transwell assays. The expressions of the genes of interest in the cells treated with everolimus (0.001- 1 μmol/L) were detected using RT-qPCR, and cell apoptosis was analyzed with flow cytometry. Western blotting was performed to assess phosphorylation levels of the key proteins in the mTORC1/p70S6K, PI3K/Akt, and Raf1/MEK/ERK pathways. Everolimus within the concentration range of 0.001-0.1 μmol/L dose-dependently inhibited RT-112-RS cell proliferation. RT-112-RS cells showed significantly enhanced migration and invasion compared with their parental RT-112 cells. Treatment with 1 μmol/L everolimus significantly suppressed p70S6K phosphorylation but did not result in an enhanced inhibition of cell proliferation effect. Everolimus at 1 μmol/L significantly activated the Raf1/MEK/ERK pathway without affecting PI3K/Akt (Thr308) or mTORC2/Akt (Ser473) phosphorylation. Treatment of the cells with the MEK inhibitor U-0126 obviously reversed everolimus-induced ERK1/2 activation, while the PI3K inhibitor LY294002 only partially reduced ERK1/2 activation in everolimus-treated cells. Everolimus inhibits RT-112-RS cell proliferation by suppressing p70S6K activity, and at high concentrations, everolimus can result in activation of the PI3K-Raf1/MEK/ERK pathway possibly by relieving negative feedback inhibition to partially offset its inhibitory effect on cell proliferation. 目的: 探讨依维莫司通过调控p70S6K/PI3K/MAPK信号通路对膀胱癌耐药细胞RT-112-RS生物学行为的影响。方法: 采用梯度法筛选厄达替尼浓度,选取5 μmol/L作为终浓度并持续诱导16周以建立厄达替尼耐药的RT-112-RS细胞模型。设对照组(RT-112-RS常规培养)、PDGF组(+PDGF-BB)、PDGF+0.01 μmol/L依维莫司组、PDGF+0.1 μmol/L依维莫司组及PDGF+1 μmol/L依维莫司组。CCK-8法测定细胞毒性并计算IC50;划痕和Transwell实验评估迁移与侵袭能力;RT-qPCR检测0.001~1 μmol/L依维莫司处理下相关基因表达;流式细胞术分析凋亡率;Western blotting检测mTORC1/p70S6K、PI3K/Akt及Raf1/MEK/ERK通路关键蛋白磷酸化水平。结果: 依维莫司在0.001~0.1 μmol/L范围内呈剂量依赖性抑制RT-112-RS增殖(P<0.05)。相比RT-112细胞,RT-112-RS迁移与侵袭能力增强(819.83±71.39 vs 1579±136.30,P<0.05)。1 μmol/L依维莫司显著抑制p70S6K磷酸化(P<0.05),但未进一步增强抗增殖效应,并特异性激活Raf1/MEK/ERK通路,对PI3K/Akt(Thr308)或mTORC2/Akt(Ser473)无明显影响。MEK抑制剂U-0126可逆转依维莫司诱导的ERK1/2活化(5.52±0.40 vs 0.74±0.07,P<0.05),PI3K抑制剂LY294002则减弱ERK1/2激活(7.58±1.54 vs 11.2±0.24,P<0.05)。结论: 依维莫司通过抑制p70S6K活性抑制RT-112-RS增殖。而高浓度时可能因减弱负反馈抑制而激活PI3K-Raf1/MEK/ERK通路,从而部分抵消其抗增殖作用。.
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PubMed · 2026-08-20
PubMed · 2026-08-20
PubMed · 2026-08-20