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    Breast Cancer Stem Cell–Derived Tumors Escape from γδ T-cell Immunosurveillance In Vivo by Modulating γδ T-cell Ligands
    (Philadelphia, Pa. : AACR, 2023) Raute, Katrin; Strietz, Juliane; Parigiani, Maria Alejandra; Andrieux, Geoffroy; Thomas, Oliver S.; Kistner, Klaus M.; Zintchenko, Marina; Aichele, Peter; Hofmann, Maike; Zhou, Houjiang; Weber, Wilfried; Boerries, Melanie; Swamy, Mahima; Maurer, Jochen; Minguet, Susana
    There are no targeted therapies for patients with triple-negative breast cancer (TNBC). TNBC is enriched in breast cancer stem cells (BCSC), which play a key role in metastasis, chemoresistance, relapse, and mortality. γδ T cells hold great potential in immunotherapy against cancer and might provide an approach to therapeutically target TNBC. γδ T cells are commonly observed to infiltrate solid tumors and have an extensive repertoire of tumor-sensing mechanisms, recognizing stress-induced molecules and phosphoantigens (pAgs) on transformed cells. Herein, we show that patient-derived triple-negative BCSCs are efficiently recognized and killed by ex vivo expanded γδ T cells from healthy donors. Orthotopically xenografted BCSCs, however, were refractory to γ δ T-cell immunotherapy. We unraveled concerted differentiation and immune escape mechanisms: xenografted BCSCs lost stemness, expression of γ δ T-cell ligands, adhesion molecules, and pAgs, thereby evading immune recognition by γ δ T cells. Indeed, neither promigratory engineered γ δ T cells, nor anti–PD-1 checkpoint blockade, significantly prolonged overall survival of tumor-bearing mice. BCSC immune escape was independent of the immune pressure exerted by the γ δ T cells and could be pharmacologically reverted by zoledronate or IFNα treatment. These results pave the way for novel combinatorial immunotherapies for TNBC.
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    Comparative Transcriptomics of Lowland Rice Varieties Uncovers Novel Candidate Genes for Adaptive Iron Excess Tolerance
    (Oxford : Oxford University Press, 2021) Kar, Saradia; Mai, Hans-Jörg; Khalouf, Hadeel; Abdallah, Heithem Ben; Flachbart, Samantha; Fink-Straube, Claudia; Bräutigam, Andrea; Xiong, Guosheng; Shang, Lianguang; Panda, Sanjib Kumar; Bauer, Petra
    Iron (Fe) toxicity is a major challenge for plant cultivation in acidic waterlogged soil environments, where lowland rice is a major staple food crop. Only few studies have addressed the molecular characterization of excess Fe tolerance in rice, and these highlight different mechanisms for Fe tolerance. Out of 16 lowland rice varieties, we identified a pair of contrasting lines, Fe-tolerant Lachit and -susceptible Hacha. The two lines differed in their physiological and morphological responses to excess Fe, including leaf growth, leaf rolling, reactive oxygen species generation and Fe and metal contents. These responses were likely due to genetic origin as they were mirrored by differential gene expression patterns, obtained through RNA sequencing, and corresponding gene ontology term enrichment in tolerant vs. susceptible lines. Thirty-five genes of the metal homeostasis category, mainly root expressed, showed differential transcriptomic profiles suggestive of an induced tolerance mechanism. Twenty-two out of these 35 metal homeostasis genes were present in selection sweep genomic regions, in breeding signatures, and/or differentiated during rice domestication. These findings suggest that Fe excess tolerance is an important trait in the domestication of lowland rice, and the identified genes may further serve to design the targeted Fe tolerance breeding of rice crops.