In vivo inhibition of c-MYC in myeloid cells impairs tumor-associated macrophage maturation and pro-tumoral activities

Although tumor-associated macrophages (TAMs) are involved in tumor growth and metastasis, the mechanisms controlling their pro-tumoral activities remain largely unknown. The transcription factor c-MYC has been recently shown to regulate in vitro human macrophage polarization and be expressed in macrophages infiltrating human tumors. In this study, we exploited the predominant expression of LysM in myeloid cells to generate c-Myc(fl/fl) LysM(cre/+) mice, which lack c-Myc in macrophages, to investigate the role of macrophage c-MYC expression in cancer. Under steady-state conditions, immune system parameters in c-Myc(fl/fl) LysM(cre/+) mice appeared normal, including the abundance of different subsets of bone marrow hematopoietic stem cells, precursors and circulating cells, macrophage density, and immune organ structure. In a model of melanoma, however, TAMs lacking c-Myc displayed a delay in maturation and showed an attenuation of pro-tumoral functions (e.g., reduced expression of VEGF, MMP9, and HIF1α) that was associated with impaired tissue remodeling and angiogenesis and limited tumor growth in c-Myc(fl/fl) LysM(cre/+) mice. Macrophage c-Myc deletion also diminished fibrosarcoma growth. These data identify c-Myc as a positive regulator of the pro-tumoral program of TAMs and suggest c-Myc inactivation as an attractive target for anti-cancer therapy

Corrigendum: Translating planetary health principles into sustainable primary care services.

[This corrects the article DOI: 10.3389/fpubh.2022.931212.]

Development of crop-specific transposable element (SINE) markers for studying gene flow from oilseed rape to wild radish

International audienceThe screening of wild populations for evidence of gene flow from a crop to a wild related species requires the unambiguous detection of crop genes within the genome of the wild species, taking into account the intraspecific variability of each species. If the crop and wild relatives share a common ancestor, as is the case for the Brassica crops and their wild relatives (subtribe Brassiceae), the species-specific markers needed to make this unambiguous detection are difficult to identify. In the model oilseed rape (Brassica napus, AACC, 2n=38)-wild radish (Raphanus raphanistrum, RrRr, 2n=18) system, we utilized the presence or absence of a short-interspersed element (SINE) at a given locus to develop oilseed rape-specific markers, as SINE insertions are irreversible. By means of sequence-specific amplified polymorphism (SINE-SSAP) reactions, we identified and cloned 67 bands specific to the oilseed rape genome and absent from that of wild radish. Forty-seven PCR-specific markers were developed from three combinations of primers anchored either in (1) the 5'- and 3'-genomic sequences flanking the SINE, (2) the 5'-flanking and SINE internal sequences or (3) the SINE internal and flanking 3'-sequences. Seventeen markers were monomorphic whatever the oilseed rape varieties tested, whereas 30 revealed polymorphism and behaved either as dominant (17) or co-dominant (13) markers. Polymorphic markers were mapped on 19 genomic regions assigned to ten linkage groups. The markers developed will be efficient tools to trace the occurrence and frequency of introgressions of oilseed rape genomic region within wild radish populations