Laboratory of Cancer Biology, Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan; Division of Pathology, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Kashiwa, Chiba, Japan.
Tsuruoka Metabolomics Laboratory, National Cancer Center, Tsuruoka, Yamagata, Japan.
Biochem Biophys Res Commun. 2020 May 21;526(1):191-198. doi: 10.1016/j.bbrc.2020.03.067. Epub 2020 Mar 20.
Collagen type I (Col I) is one of the major extracellular matrix proteins in the cancer tissue. Previously, we have reported that Col I induces epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance by mTOR activation through Akt and ERK1/2 independent pathway. In this study, we aimed to elucidate the molecular mechanism of Col I induced EGFR-TKI resistance. First, we demonstrated the uptake of fluorescently labeled Col I by EGFR-mutated lung cancer cell line PC-9 cells using confocal microscopy and flow cytometry. Metabolome analysis revealed that the metabolic profiles of PC-9 cells was influenced by Col I treatment. Uptake of Col I into PC-9 cells was not inhibited by MMP inhibitor, GM6001, and endocytosis inhibitors, Pitstop2 and Dyngo4a; however, macropinocytosis inhibitor EIPA prevented its uptake. Moreover, the combination of EIPA and EGFR-TKI abrogated Col I-induced EGFR-TKI resistance in PC-9 cells. Inhibition of Rac1, which is essential for micropinocytosis, also decreased the uptake of Col I in PC-9 cells and restored their sensitivity to EGFR-TKI. Thus, EGFR mutated lung cancer cells could develop EGFR-TKI resistance by Col I uptake by macropinocytosis route.
胶原 I 型（Col I）是癌症组织中主要的细胞外基质蛋白之一。之前，我们已经报道 Col I 通过 Akt 和 ERK1/2 非依赖性途径激活 mTOR 诱导表皮生长因子受体酪氨酸激酶抑制剂（EGFR-TKI）耐药。在这项研究中，我们旨在阐明 Col I 诱导 EGFR-TKI 耐药的分子机制。首先，我们使用共聚焦显微镜和流式细胞术证实了荧光标记的 Col I 被 EGFR 突变型肺癌细胞系 PC-9 细胞摄取。代谢组学分析显示 Col I 处理影响了 PC-9 细胞的代谢谱。MMP 抑制剂 GM6001 和内吞作用抑制剂 Pitstop2 和 Dyngo4a 均不能抑制 Col I 进入 PC-9 细胞；然而，巨胞饮抑制剂 EIPA 可阻止其摄取。此外，EIPA 和 EGFR-TKI 的联合使用可消除 Col I 诱导的 PC-9 细胞 EGFR-TKI 耐药性。抑制对微胞饮至关重要的 Rac1 也减少了 PC-9 细胞中 Col I 的摄取，并恢复了它们对 EGFR-TKI 的敏感性。因此，EGFR 突变型肺癌细胞可通过巨胞饮途径摄取 Col I 而产生 EGFR-TKI 耐药性。
