1. Pyrotinib Sensitizes 5-Fluorouracil-Resistant HER2+ Breast Cancer Cells to 5-Fluorouracil
- Author
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Lianhong Zou, Pingyong Yi, Chen Shuai, Jianing Yi, Fang Meng, Peizhi Fan, Yang Du, and Jinlin Luo
- Subjects
Cancer Research ,Receptor, ErbB-4 ,Abcg2 ,Receptor, ErbB-2 ,Down-Regulation ,Antineoplastic Agents ,Breast Neoplasms ,030226 pharmacology & pharmacy ,Thymidylate synthase ,Article ,Mice ,03 medical and health sciences ,Breast cancer ,0302 clinical medicine ,ErbB ,In vivo ,HER2 ,Cell Line, Tumor ,Antineoplastic Combined Chemotherapy Protocols ,5-Fluorouracil (5-FU) ,medicine ,Animals ,Humans ,RNA, Messenger ,Protein Kinase Inhibitors ,Acrylamides ,Mice, Inbred BALB C ,biology ,Chemistry ,Thymidylate Synthase ,General Medicine ,Pyrotinib ,medicine.disease ,In vitro ,ErbB Receptors ,Oncology ,Drug Resistance, Neoplasm ,Fluorouracil ,Cell culture ,030220 oncology & carcinogenesis ,Aminoquinolines ,biology.protein ,Cancer research ,Female ,Proto-Oncogene Proteins c-akt ,Chemoresistance ,medicine.drug - Abstract
5-Fluorouracil (5-FU) is a widely used chemotherapeutic agent for breast cancer. However, acquired chemoresistance leads to a loss of its efficacy; methods to reverse are urgently needed. Some studies have shown that pyrotinib, an ErbB receptor tyrosine kinase inhibitor, is effective against HER2+ breast cancer. However, whether pyrotinib sensitizes 5-FU-resistant breast cancer cells to 5-FU is unknown. We hypothesized that the combination of pyrotinib and 5-FU would show synergistic antitumor activity, and pyrotinib could reverse 5-FU resistance in HER2+ breast cancer cells in vitro and in vivo. Our data showed that pyrotinib inhibited the growth of 5-FU-resistant SKBR-3/FU and MDA-MB-453/FU cell lines and the parental cell lines. 5-FU remarkably suppressed the growth of SKBR-3 and MAD-MB-453 cells. However, SKBR-3/FU and MAD-MB-453/FU cells showed resistance to 5-FU. A combination of pyrotinib and 5-FU resulted in the synergistic inhibition of the growth of the 5-FU-resistant SKBR-3/FU and MDA-MB-453/FU cell lines and the parental cell lines. Pyrotinib decreased significantly the IC50 values of 5-FU and the thymidylate synthase (TS) mRNA expression levels in the 5-FU-resistant SKBR-3/FU and MDA-MB-453/FU cell lines and the parental cell lines and increased significantly the intracellular concentration of 5-FU in SKBR-3/FU and MDA-MB-453/FU cells. In addition, pyrotinib reduced the ABCG2 mRNA and protein expression levels in SKBR-3/FU and MDA-MB-453/FU cells and downregulated the protein expression levels of pAKT, pHER2, and pHER4 in all four cell lines. After TS or ABCG2 in 5-FU-resistant breast cancer cells was knocked down, the sensitivity of SKBR-3/FU and MDA-MB-453/FU cells to 5-FU was restored. Moreover, in vivo experiments demonstrated that pyrotinib in combination with 5-FU more effectively inhibited SKBR-3/FU tumor growth than either pyrotinib or 5-FU alone. In conclusion, our findings suggest that pyrotinib could restore sensitivity of 5-FU-resistant HER2+ breast cancer cells to 5-FU through downregulating the expression levels of TS and ABCG2.
- Published
- 2020