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Biology subjects

Norkin, M.

Publications and source records attributed to Norkin, M..

2 recordsLinked to original sources

Deciphering spatial heterogeneity of patient-derived organoids of colorectal tumors for drug discovery

The spatial organization of tumors is critical for drug development, as spatial heterogeneity in cancer cells and the tumor microenvironment can present a significant barrier to effective therapies. Patient-derived tumor organoids (PDOs) offer promising platforms to study tumor biology and for drug development. Previous studies have demonstrated that PDOs can maintain the genomic/clonal heterogeneity of tumors, as well as expression heterogeneity. However, the spatial heterogeneity of PDOs and its correlation with the original tumors remains unclear. We propose an integrated pipeline combining spatial transcriptomics and phenotypic analyses of PDOs to capture and track spatial heterogeneity. This platform integrates multiplexed organoid cultures with imaging-based spatial transcriptomics and analysis at single organoid resolution. We validate the platform by comparing results with non-spatial single-cell transcriptomic data and spatial transcriptomic analysis of donor tumors. The combination of ex vivo PDOs and spatial transcriptomics could open novel avenues for developing drugs.

cancer biology↗

Distinct genetic pathways define pre-leukemic and compensatory clonal hematopoiesis in Shwachman-Diamond syndrome

Shwachman-Diamond syndrome (SDS) is an inherited bone marrow failure syndrome with predisposition to developing leukemia. We found that multiple independent somatic hematopoietic clones arise early in life, most commonly harboring heterozygous mutations in EIF6 or TP53. EIF6 mutations cause functional compensation for the germline deficiency by alleviating the SDS ribosome joining defect, improving translation, and reducing p53 activation. TP53 mutations decrease checkpoint activation without affecting ribosome assembly. We link development of leukemia with acquisition of biallelic TP53 alterations. Our results define distinct pathways of clonal selection driven by germline fitness constraint and provide a mechanistic framework for clinical surveillance.

cancer biology↗