JAK2 regulates paclitaxel resistance in triple negative breast cancers

• Published in: Journal of molecular medicine (Berlin, Germany) Germany), 2021-12, Vol.99 (12), p.1783-1795
• Main Authors: Han, Jongmin, Yun, Jihui, Quan, Mingji, Kang, Wonyoung, Jung, Ji-Gwang, Heo, Woohang, Li, Songbin, Lee, Kyu Jin, Son, Hye-Youn, Kim, Ju Hee, Choi, Jaeyong, Noh, Dong-Young, Na, Deukchae, Ryu, Han Suk, Lee, Charles, Kim, Jong-Il, Moon, Hyeong-Gon
• Format: Article
• Language: English
• Subjects: Animals; Antineoplastic Agents, Phytogenic - pharmacology; Antineoplastic Agents, Phytogenic - therapeutic use; Biomedical and Life Sciences; Biomedicine; Breast cancer; Cancer; Cancer-Associated Fibroblasts - metabolism; Cell culture; Cell cycle; Cell Line, Tumor; Copy number; Drug Resistance, Neoplasm - genetics; Female; Fibroblasts; Gene Expression Regulation, Neoplastic - drug effects; Genes; Human Genetics; Humans; Internal Medicine; Janus kinase; Janus kinase 2; Janus Kinase 2 - antagonists & inhibitors; Janus Kinase 2 - genetics; Janus Kinase 2 - metabolism; Mammary Neoplasms, Experimental - drug therapy; Mammary Neoplasms, Experimental - genetics; Mammary Neoplasms, Experimental - metabolism; Mice; Molecular Medicine; Molecular modelling; Nitriles - pharmacology; Original Article; Paclitaxel; Paclitaxel - pharmacology; Paclitaxel - therapeutic use; Phenotypes; Pyrazoles - pharmacology; Pyrimidines - pharmacology; Transcriptomes; Triple Negative Breast Neoplasms - drug therapy; Triple Negative Breast Neoplasms - genetics; Triple Negative Breast Neoplasms - metabolism; Tumor microenvironment; Tumor Microenvironment - drug effects; Tumors; Xenografts
• ISSN: 0946-2716; 1432-1440
• DOI: 10.1007/s00109-021-02138-3

We investigated the molecular mechanisms of paclitaxel resistance in TNBC using seven patient-derived xenograft (PDX) models and TNBC cell lines. Among the seven PDX models, four models showed resistance to paclitaxel. Dysregulation of JAK/STAT pathways and JAK2 copy number gains were observed in the four paclitaxel-resistant PDX tumors. In TNBC cell lines, silencing the JAK2 gene showed a significant but mild synergistic effect when combined with paclitaxel in vitro. However, JAK1/2 inhibitor treatment resulted in restoration of paclitaxel sensitivity in two out of four paclitaxel-resistant PDX models and JAK1/2 inhibitor alone significantly suppressed the tumor growth in one out of the two remaining PDX models. Transcriptome data derived from the murine microenvironmental cells revealed an enrichment of genes involved in the cell cycle processes among the four paclitaxel-resistant PDX tumors. Histologic examination of those PDX tumor tissues showed increased Ki67-positive fibroblasts in the tumor microenvironment. Among the four different cancer-associated fibroblast (CAF) subtypes, cycling CAF exhibiting features of active cell cycle was enriched in the paclitaxel-resistant PDX tumors. Additionally, fibroblasts treated with the conditioned media from the JAK2-silenced breast cancer cells showed downregulation of cell cycle-related genes. Our data suggest that the JAK2 gene may play a critical role in determining responses of TNBC to paclitaxel by modulating the intrinsic susceptibility of cancer cells against paclitaxel and also by eliciting functional transitions of CAF subtypes in the tumor microenvironment. Key messages We investigated the molecular mechanisms of paclitaxel resistance in TNBC. JAK2 signaling was associated with paclitaxel resistance in TNBC PDX models. Paclitaxel-resistant PDX tumors were enriched with microenvironment cCAF subpopulation. JAK2 regulated paclitaxel-resistant CAF phenotype transition.