Tumor stem-like cell-derived exosomal RNAs prime neutrophils for facilitating tumorigenesis of colon cancer

Abstract

BackgroundCell-cell interactions maintain tissue homeostasis and contribute to dynamic alteration of the tumor microenvironment (TME). Communication between cancer and host cells not only promotes advanced disease aggression but also determines therapeutic response in cancer patients. Despite accumulating evidence supporting the role of tumor-infiltrating immunocytes in modulating tumor immunity, the interplay between heterogeneous tumor subpopulations and immunocytes is elusive.MethodsWe expanded colorectal cancer stem cells (CRCSCs) as cancer spheroids from the murine colorectal cancer (CRC) cell line CT26 to interrogate tumor-host interactions using a syngeneic tumor model. RNA-sequencing analysis of host cells and tumor exosomes was performed to identify molecular determinants that mediate the crosstalk between CRCSCs and immunocytes. The Cancer Genome Atlas (TCGA) database was used to validate the clinical significance in CRC patients.ResultsThe expanded CT26 cancer spheroids showed increased stemness gene expression, enhanced spheroid and clonogenicity potential, and an elevated tumor-initiating ability, characteristic of CRCSCs. By examining immune cell composition in syngeneic tumor-bearing mice, a systemic increase in CD11b+/Ly6GHigh/Ly6CLow neutrophils was observed in mice bearing CRCSC-derived tumors. An increased secretion of CRCSC exosomes was observed in vitro, and through in vivo tracking, CRCSC exosomes were found to be transported to the bone marrow. Moreover, CRCSC exosomes prolonged the survival of bone marrow-derived neutrophils and engendered a protumoral phenotype in neutrophils. Mechanistically, tumor exosomal tri-phosphate RNAs induced the expression of interleukin-1β (IL-1β) through a pattern recognition-NF-κB signaling axis to sustain neutrophil survival. CRCSC-secreted CXCL1 and CXCL2 then attracted CRCSC-primed neutrophils to promote tumorigenesis of CRC cells via IL-1β. Moreover, neutrophil depletion using a Ly6G-specific antibody (clone 1A8) attenuated the tumorigenicity of CRCSCs. In human specimens, CRC patients exhibiting an active CRCSC signal (Snail+IL8+) showed elevated tumor infiltration of MPO+ neutrophils, and high (in the top 10%) MPO expression predicted poor survival of CRC patients.ConclusionsThis study elucidates a multistep CRCSC-neutrophil interaction during advanced cancer progression. Strategies targeting aberrant neutrophil activation may be developed for combating CSC-related malignancy.Electronic supplementary materialThe online version of this article (10.1186/s13045-019-0699-4) contains supplementary material, which is available to authorized users.

Exosomal MALAT1 sponges miR-26a/26b to promote the invasion and metastasis of colorectal cancer via FUT4 enhanced fucosylation and PI3K/Akt pathway

“…Exosomes, membrane vesicles of endocytic origin ranging in size from 30 to 150 nm approximately, are emerging as key players in intercellular communication between cancer cells and their microenvironment [5]. A distinct feature of exosomes is that they efficiently carry and deliver molecular signatures (proteins, lipids, RNA…”

“…To the best of our knowledge, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) are well established tumor markers with low sensitivity and specificity for early detection of CRC [4]. Hence, ideal CRC-specific biomarkers are urgently required to improve the current CRC diagnostic strategies.Exosomes, membrane vesicles of endocytic origin ranging in size from 30 to 150 nm approximately, are emerging as key players in intercellular communication between cancer cells and their microenvironment [5]. A distinct feature of exosomes is that they efficiently carry and deliver molecular signatures (proteins, lipids, RNA…”

Cancer Stem Cell-Exosomes, Unexposed Player in Tumorigenicity

“…For example, it was reported that glioblastoma stem cell-derived exosomes direct monocytes toward the immune suppressive "M2" phenotype, through the signal transducer and activator of transcription-3 (STAT3) pathway, creating an immunosuppressive microenvironment (Gabrusiewicz et al, 2018). While colorectal cancer stem cellderived exosomes promote a pro-tumoral phenotype in neutrophils by increasing interleukin-(IL)-1b expression (Hwang et al, 2019) Since tumor-host cross-talk is believed to be initiated by CSCs, and communication between cancer cells and other cells is conducted through exosomes, it's of great importance to take a closer look at the role of CSCs-exosomes, and its involvement in Western Blot analysis revealed up regulation of PD-L1 in exosome-treated monocytes. PD-L1 correlates with increased STAT3 pathway phosphorylation, which mediate this immune suppressive switch.…”

“…(Gabrusiewicz et al, 2018) Exosomes derived from spheroid formations of colorectal cancer cell line Prompted a pro-tumoral phenotype in neutrophils miRNA and ELISA analysis revealed elevated levels of IL-1b in exosometreated neutrophils and their condition medium. (Hwang et al, 2019) PTEN, phosphatase and tensin homolog; MALTA1, metastasis associated lung adenocarcinoma transcript 1; PD-l1, programmed death-ligand 1; ELISA, enzyme-linked immunosorbent assay.…”

Colorectal cancer stem cells properties and features: evidence of interleukin-8 involvement

“…Very recently, the same group demonstrated that CRC patients, who expressed the specific CRCSC activation pattern Snail + /IL-8 + , display increased MyeloPerOxidase (MPO) + neutrophils which correlate with poor patient survival [63] . According to these data, Roncucci et al [64] showed that patients with CRC display higher number of MPO + cells in normal mucosa rather than controls, and that MPO + levels increase during carcinogenesis.…”