CYP3A4 and colon carcinoma: The top calcitriol-upregulated genes in both types of organoids were the known calcitriol targets CYP24A1, CYP3A4, TRPV6, and PRSS33. Among the top-downregulated genes, we found P2RX1 and DKK4, with the latter described as repressed by calcitriol in colon carcinoma cells [55,56].