Abstract 4763: Metronomic chemotherapy prevents therapy-induced stromal activation and induction of cancer stem cells

Abstract

Abstract Whilst traditional chemotherapy kills a fraction of tumor cells, it also activates the stroma and can promote the growth and survival of residual cancer cells to foster tumor recurrence and metastasis. Accordingly, overcoming the host response induced by chemotherapy could substantially improve therapeutic outcome and patient survival. Treatment resistance and metastasis have been attributed to expansion of cancer stem-like cells (CSCs). Molecular analysis of the tumor stroma in neoadjuvant chemotherapy-treated human desmoplastic cancers and orthotopic tumor xenografts revealed that traditional maximal tolerated dose chemotherapy, regardless of the agents used, induces persistent STAT-1 and NF-κB activity in carcinoma-associated fibroblasts that induces the expression and secretion of ELR-motif-positive (ELR+) chemokines, which signal through CXCR-2 on carcinoma cells to trigger their phenotypic conversion into CSCs and promote their invasive behaviors, leading to paradoxical tumor aggression following the therapy. By contrast, the same total accumulated dose administered as a low-dose-metronomic chemotherapy regimen largely prevented the therapy-induced stromal ELR+-chemokine paracrine signaling for CSCs, thereby substantially enhancing treatment response and extending survival of mice carrying desmoplastic cancers (Chan et al, J. Exp. Med. 2016). These studies illustrate the importance of stroma in cancer therapy and how its impact on treatment resistance could be tempered by altering the dosing schedule of systemic chemotherapy. Note: This abstract was not presented at the meeting. Citation Format: Kelvin K. Tsai, Tze-Sian Chan, Chung-Chi Hsu, Vincent C. Pai, Shenq-Shyang Huang, Valerie M. Weaver. Metronomic chemotherapy prevents therapy-induced stromal activation and induction of cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4763. doi:10.1158/1538-7445.AM2017-4763