Screening Five Qi-Tonifying Herbs on M2 Phenotype Macrophages

Abstract

Tumor-associated macrophages (TAMs) with M2 phenotype play an essential role in tumor microenvironment (TME) during the progression and development of numerous cancers and associated with poor prognosis. Thus, regulation of TAMs polarization emerged as a new strategy for tumor immune therapy. According to Traditional Chinese Medicine (TCM) theory, herbs with Qi-tonifying character are involved in improving the defense capacity of immune system. In this study, we screened extracts and ingredients from five Qi-tonifying herbs exhibiting an inhibitory effect on M2 polarization of murine macrophages RAW264.7 induced by IL-4 and IL-13. Among these candidates, total flavonoids from Glycyrrhiza Radix et Rhizoma (TFRG) and ethanol extract of Ginseng Radix et Rhizoma significantly inhibited the expression of Arginase-1 (Arg-1) (above 90% at 100μg/mL), one of the phenotype markers of M2 macrophages. The inhibition of total saponins of Ginseng Radix et Rhizoma, ethanol extract of Cordyceps, ethanol extract of Acanthopanacis senticosi Radix et Rhizoma Seu caulis, and ethanol extract of Astragali Radix reached above 50% at 100μg/mL. The inhibition of ingredients including glabridin, isoliquiritin apioside, lysionotin, cordycepin, astragaloside IV, and calycosin reached above 50% at 50μM. Then, we investigated the molecular mechanisms of TFRG. TFRG abolished the migration of murine breast cancer 4T1 stimulated by the conditioned medium from M2 macrophages (M2-CM). In addition to Arg-1, TFRG also antagonized the IL-4/13-mediated mRNA upregulation of the M2 markers including found in inflammatory zone 1 (FIZZ1), chitinase-3-like protein 3 (YM1), and mannose receptor (CD206) and upregulated the expression of inducible nitric oxide synthase (iNOS), one of the M1 markers. The further exploration showed that TFRG decreased the phosphorylation of STAT6 and increased the expression of miR-155. Our study provides a series of potential immune regulating natural products from five Qi-tonifying herbs on M2 phenotype. For instance, TFRG suppressed M2 polarization of macrophages partly by inactivating STAT6 pathway and enhanced the level of miR-155 to regulate the expressions of M1 and M2 markers.

Targeting Tumor-Associated Macrophages by Plant Compounds

“…The transcription and production of TGF-β and IL-10, two well-known immunosuppressive cytokines secreted by TAMs, were reduced in response to Panax polysaccharides and also the number of infiltrated CD168+ M2 TAMs was substantially declined although the number of CD68+ total macrophages in transplanted tumor tissues remained almost unchanged [81]. A significant inhibition of Arg-1 expression (above 90% at 100 μg/mL), one of the phenotype markers of M2 macrophages, was also observed for the ethanol extract of Ginseng Radix et Rhizoma [62]. Recently, Chen et al [82], showed that water extract of Ginseng and Astragalus could be a novel option for integrative cancer therapies due mainly to their ability to regulate macrophage polarization.…”

“…Total flavonoids from Glycyrrhizae Radix et Rhizoma significantly inhibited the expression of Arg-1 (above 90% at 100 μg/mL), one of the phenotype markers of M2 macrophages, and suppressed M2 polarization of macrophages partly by inactivating STAT6 pathway. The regulation of M1 and M2 markers' expressions was partly due to the enhancement of miR-155 levels [62].…”

A survey of herbal medicines as tumor microenvironment‐modulating agents

“…Curcumin, DHA, EGCG, resveratrol, and silibinin have been shown to modulate more than two components of the TME. As a single herb, Glycyrrhiza Radix et Rhizoma exhibited the most potent effect in the normalization of TAMs (Jiang et al, 2019). Hochu-ekki-to (Bojungikki-tang) and Keishi-bukuryo-gan (Gyejibokryeong-hwan) can reverse the immunosuppressive function of MDSCs (Koga et al, 2017), while HangAmDan-B can promote M1 polarization (Park et al, 2017).…”

“…Moreover, epoxydocosapentaenoic acid treatment interfered with the interaction between VEGF and VEGF receptor 2, resulting in impaired tumor angiogenesis (Zhang et al, 2013a). macrophage-induced 4T1 breast cancer cell migration (Jiang et al, 2019).…”

<p>Effect and Molecular Mechanisms of Traditional Chinese Medicine on Tumor Targeting Tumor-Associated Macrophages</p>

“…In addition, accumulating evidence has suggested that the polarized-M2 phenotype could increase the proliferation, migration and invasion abilities of cancer cells. 18,23,46 Zhao et al [47][48][49] found that M2-TAMs enhanced metastasis by improving the migration capacity of breast cancer 4T1 cells. In addition, Pang et al 46 found that culturing NSCLC cells with M2-polarized TAMconditioned medium (TAM-CM) ultimately led to stronger proliferation, migration, and invasion than culturing these cells in routine medium (Figure 2).…”