Project description:The individualized treatment of tumors has always been an urgent problem in clinical practice. Organoids-on-a-chip can reflect the heterogeneity of tumors and is a good model for in vitro anticancer drug screening. In this study, surgical specimens of patients with advanced colorectal cancer will be collected for organoid culture and organoids-on-a- chip. Use organoids-on-a-chip to screen tumor chemotherapy drugs, compare the results of patients’ actual medication regimens, and study the guiding role of organoids in the formulation of precise tumor treatment plans. The investigators will compare the response of organoids to drugs in vitro with the patient’s response to actual chemotherapy and targeted drugs and explore the feasibility and accuracy of organoids-on-a-chip based drug screening for advanced colorectal cancer. The project will establish a screening platform for chemotherapeutic drugs and targeted drugs based on colorectal cancer organoids to quickly and accurately formulate personalized treatment plans for clinical patients.
Project description:We reported transcriptional characterization of Treg cells, Tconv cells, and DCs isolated from coloinc lamina propria of Vdr WT- or Vdr KO-Foxp3 reporter mice. We also reported transcriptional characterization of colonic ECs isolated from Vdr WT- or Vdr KO-Foxp3 reporter mice.
Project description:Background & Aims: Active vitamin D, 1α,25(OH)2D3, is a nuclear hormone with roles in colonic homeostasis and carcinogenesis, yet mechanisms underlying these effects are incompletely understood. Human organoids are an ideal system to study genomic and epigenomic host-environment interactions. Here, we utilize human colonic organoids to measure 1α,25(OH)2D3 responses on genome-wide gene expression and chromatin accessibilityover time. Methods: Human colonic organoids were cultured and treated in triplicate with either 100nM 1α,25(OH)2D3 or vehicle control for 4 and 18 hours (h) for chromatin accessibility, and 6 and 24hfor gene expression. DNA and RNA were extracted for ATAC- and RNA-sequencing, respectively. Differentially accessible peaks were analyzed using DiffBind and EdgeR; differentially expressed genes were analyzed using DESeq2. Motif enrichment was determined using HOMER. Results: At 6h and 24h, 2870 and 2721 differentially expressed genes, respectively (FDR<5%) were identified with overall stronger responses with 1α,25(OH)2D3. Similarly, 1α,25(OH)2D3 treatment led to stronger chromatin accessibility especially at 4h. The vitamin D receptor (VDR) motif was strongly enriched among open chromatin peaks with 1α,25(OH)2D3 treatment accounting for 30.5% and 11% of target sequences at 4h and 18h, respectively (FDR<1%). A number of genes such as CYP24A1, FGF19, MYC, FOS and TGFBR2 showed significant transcriptional and chromatin accessibility responses to 1α,25(OH)2D3 treatment with open chromatin located distant from promoters for some gene regions. Conclusions: Assessment of chromatin accessibility and transcriptional responses to 1α,25(OH)2D3 yielded new observations about vitamin D genome-wide effects in the colon facilitated by application of human colonic organoids. This framework can be applied to study host-environment interactions between individuals and populations in future.
Project description:VitaminD deficiency has been related to a higher incidence of colorectal cancer. In order to further study the effect of VDR and its ligand as genome modulators we established stem cell enriched cultures of wt and VDR KO mice, treated with the active metabolite of Vitamin D and analyzed the changes in total RNA expression.
Project description:We performed ChIP-seq in macrophage-type PMA-differentiated THP-1 cells after stimulation with the the natural VDR ligand 1,25dihydroxyvitamin D3 (1,25D). We identified in total 223 VDR binding locations on chromatin after 1,25D treatment. De novo analysis of VDR site sequences identified DR3-type binding sites as major motif.