Tumor-associated macrophages respond to chemotherapy by detrimental transcriptional reprogramming and suppressing stabilin-1 mediated clearance of EGF

Abstract

IntroductionTumor resistance to chemotherapy and metastatic relapse account for more than 90% of cancer specific mortality. Tumor-associated macrophages (TAMs) can process chemotherapeutic agents and impair their action. Little is known about the direct effects of chemotherapy on TAMs.MethodsThe effect of chemotherapeutic platinum agent cisplatin was assessed in the model system of human ex vivo TAMs. Whole-transcriptome sequencing for paired TAMs stimulated and not stimulated by cisplatin was analysed by NGS. Endocytic uptake of EGF was quantified by flow cytometry. Confocal microscopy was used to visualize stabilin-1-mediated internalization and endocytic trafficking of EGF in CHO cells expressing ectopically recombinant stabilin-1 and in stabilin-1+ TAMs. In cohort of patients with breast cancer, the effect of platinum therapy on the transcriptome of TAMs was validated, and differential expression of regulators of endocytosis was identified.ResultsHere we show that chemotherapeutic agent cisplatin can initiate detrimental transcriptional and functional programs in TAMs, without significant impairment of their viability. We focused on the clearance function of TAMs that controls composition of tumor microenvironment. For the first time we demonstrated that TAMs’ scavenger receptor stabilin-1 is responsible for the clearance of epidermal growth factor (EGF), a potent stimulator of tumor growth. Cisplatin suppressed both overall and EGF-specific endocytosis in TAMs by bidirectional mode: suppression of positive regulators and stimulation of negative regulators of endocytosis, with strongest effect on synaptotagmin-11 (SYT11), confirmed in patients with breast cancer.ConclusionOur data demonstrate that synergistic action of cytostatic agents and innovative immunomodulators is required to overcome cancer therapy resistance.

Modelling of macrophage responses to biomaterials in vitro: state-of-the-art and the need for the improvement

“…Thus outcome of different SR activities will be the decision of monocytes and macrophage to guard homeostatic balance, or to create chronic inflammatory microenvironment that frequently is further complicated by fibrosis ( 56 ). Scavenger receptor on macrophages play an essential role in clearing and removing not only of cellular debris, apoptotic cells, but also fibrin, and growth factors, including epithelial growth factor (EGF) and GDF-15 ( 55 , 60 – 62 ). To carry out this analysis, an in vitro endocytosis or phagocytosis tests can be used.…”

Macrophages as a Source and Target of GDF-15

“…It is also present in resident macrophages, excluding Kupffer cells, and in tumor-associated macrophages (TAMs). Macrophages in inflamed or healing cardiac tissue also show expression of stabilin-1 [76][77][78][79][80][81]. Macrophages express stabilin-1 in response to IL-4 and dexamethasone, thus stabilin-1 is considered a marker of M2 polarization [82].…”

Macrophages and platelets in liver fibrosis and hepatocellular carcinoma

“…A phase II clinical trial testing Clever-1 inhibition using a humanized anti-Clever-1 antibody in 10 distinct, advanced solid tumor types (e.g., melanoma, pancreatic, liver cancer) already showed promising results ( 166 , 167 ). Finally, Clever-1 on TAMs was recently shown to be responsible for epidermal growth factor (EGF) clearance, a highly relevant tumor promoter ( 168 ).…”

“…Preclinical studies showed that human monocytes expressing high levels of Clever-1 impaired Th1 T cell activation, which was reversed via siRNA knockdown or a blocking antibody (164) and that targeting Clever-1 in TAMs via macrophage-specific genetic knockout or via antibody blockade retarded the growth of LLC1 Lewis lung carcinoma cells in vivo, by inducing a robust CD8 T cell response (165). A phase II clinical trial testing Clever-1 inhibition using a humanized anti-Clever-1 antibody in 10 distinct, advanced solid tumor types (e.g., melanoma, pancreatic, liver cancer) already showed promising results (166,167). Finally, Clever-1 on TAMs was recently shown to be responsible for epidermal growth factor (EGF) clearance, a highly relevant tumor promoter (168).…”