Dataset Information

Microenvironment mediated alterations to metabolic pathways confer increased chemo-resistance in CD133+ tumor initiating cells.

ABSTRACT: Chemoresistance in pancreatic cancer has been attributed to tumor-initiating cells (TICs), a minor sub-population of tumor cells. However, the mechanism of chemo-resistance in these cells is still unclear.In the current study, immunohistochemical analysis of LSL-KrasG12D; LSL-Trp53R172H;PdxCre (KPC) murine tumors indicated that hypoxic regions developed through tumor progression. This hypoxic "niche" correlated with increased CD133+ population that had an increased HIF1A activity. Consistent with this observation, CD133+ cells had increased glucose uptake and activity of glycolytic pathway enzymes compared to CD133- cells. Mass spectrometric analysis (UPLC-TQD) following metabolic labeling of CD133+ cells with [13C]-U6 glucose confirmed this observation. Furthermore, although both populations had functionally active mitochondria, CD133+ cells had low mitochondrial complex I and complex IV activity and lesser accumulation of ROS in response to standard chemotherapeutic compounds like paclitaxel, 5FU and gemcitabine. CD133+ cells also showed increased resistance to all three chemotherapeutic compounds and treatment with Glut1 inhibitor (STF31) reversed this resistance, promoting apoptotic death in these cells similar to CD133- cells.Our study indicates that the altered metabolic profile of CD133+ pancreatic TIC protects them against apoptosis, by reducing accumulation of ROS induced by standard chemotherapeutic agents, thereby confering chemoresistance. Since resistance to existing chemotherapy contributes to the poor prognosis in pancreatic cancer, our study paves the way for identifying novel therapeutic targets for managing chemoresistance and tumor recurrence in pancreatic cancer.

SUBMITTER: Nomura A

PROVIDER: S-EPMC5302917 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BACKGROUND AND AIMS:Changes in single microRNA (miRNA) expression have been associated with chemo-resistance in biliary tract cancers (BTCs). However, a global assessment of the dynamic role of the microRNome has never been performed to identify potential therapeutic targets that are functionally relevant in the BTC cell response to chemotherapy. APPROACH AND RESULTS:High-throughput screening (HTS) of 997 locked nucleic acid miRNA inhibitors was performed in six cholangiocarcinoma cell lines treated with cisplatin and gemcitabine (CG) seeking changes in cell viability. Validation experiments were performed with mirVana probes. MicroRNA and gene expression was assessed by TaqMan assay, RNA-sequencing, and in situ hybridization in four independent cohorts of human BTCs. Knockout of microRNA was achieved by CRISPR-CAS9 in CCLP cells (MIR1249KO) and tested for effects on chemotherapy sensitivity in vitro and in vivo. HTS revealed that MIR1249 inhibition enhanced chemotherapy sensitivity across all cell lines. MIR1249 expression was increased in 41% of cases in human BTCs. In validation experiments, MIR1249 inhibition did not alter cell viability in untreated or dimethyl sulfoxide-treated cells; however, it did increase the CG effect. MIR1249 expression was increased in CD133+ biliary cancer cells freshly isolated from the stem cell niche of human BTCs as well as in CD133+ chemo-resistant CCLP cells. MIR1249 modulated the chemotherapy-induced enrichment of CD133+ cells by controlling their clonal expansion through the Wnt-regulator FZD8. MIR1249KO cells had impaired expansion of the CD133+ subclone and its enrichment after chemotherapy, reduced expression of cancer stem cell markers, and increased chemosensitivity. MIR1249KO xenograft BTC models showed tumor shrinkage after exposure to weekly CG, whereas wild-type models showed only stable disease over treatment. CONCLUSIONS:MIR1249 mediates resistance to CG in BTCs and may be tested as a target for therapeutics.

Project description:Experimental data indicate that colorectal cancer cells with CD133 expression exhibit enhanced tumorigenicity over CD133-negative (CD133-) cells. We hypothesized that CD133-positive (CD133+) cells, compared with CD133-, are more tumorigenic because they are more interactive with and responsive to their stromal microenvironment. Freshly dissected and dissociated cells from a primary colon cancer were separated into carcinoma-associated fibroblasts (CAF) and the epithelial cells; the latter were further separated into CD133+ and CD133- cells using fluorescence-activated cell sorter. The CD133+ cells formed large tumors in non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice, demonstrating the phenotypic cellular diversity of the original tumor, whereas CD133- cells were unable to sustain significant growth. Affymetrix gene array analyses using t-test, fold-change and multiple test correction identified candidate genes that were differentially expressed between the CD133+ vs CD133- cells. RT-PCR verified differences in expression for 30 of the 46 genes selected. Genes upregulated (+ vs - cells) included CD133 (9.3-fold) and CXCR4 (4-fold), integrin ?8 and fibroblast growth factor receptor 2. The CAF highly express the respective ligands: stromal-derived factor-1 (SDF-1), vitronectin and FGF family members, suggesting a reciprocal relationship between the CD133+ and CAF cells. SDF-1 caused an increase in intracellular calcium in cells expressing both CD133 and CXCR4, confirming functional CXCR4. The CD133+/CXCR4+ phenotype is increased to 32% when the cells are grown in suspension compared with only 9% when the cells were allowed to attach. In Matrigel 3-D culture, the CD133+/CXCR4+ group treated with SDF-1 grew more colonies compared with vehicle, as well as significantly larger colony sizes of tumor spheres. These data demonstrate proof of principle that the enhanced tumorigenic potential of CD133+, compared with CD133-, cells is due to their increased ability to interact with their neighboring CAF.

Dataset Information

Microenvironment mediated alterations to metabolic pathways confer increased chemo-resistance in CD133+ tumor initiating cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets