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D.K. Mishra



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    P1.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 233)

    • Event: WCLC 2015
    • Type: Poster
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 1
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      P1.04-102 - Ex Vivo 4D Lung Cancer Model CTCs Show Resistance to Chemotherapeutic Drugs (ID 245)

      09:30 - 17:00  |  Author(s): D.K. Mishra

      • Abstract
      • Slides

      Background:
      Metastasis is the main cause of cancer-associated mortality. We recently developed an ex vivo 4D lung cancer model that mimics metastasis. One of the unique features of the model is its ability to isolate tumor cells in three different phases of cancer progression: primary tumors, circulating tumor cells (CTCs), and metastatic lesions. In this study, we want to further characterize the CTCs from the model and determine whether they enter a resting cell cycle phase, and conferring them to be resistant to chemotherapeutic drugs.

      Methods:
      We harvested rat lung and heart block and decellularized them using 0.1% sodium dodecyl sulfate and 1% Triton-X100. Acellular lung scaffolds were set up in a customized bioreactor and seeded with 50 million cells of human lung cancer cell line H1299 that were cultured on a petri dish (2D). Culture media was replenished and CTCs were collected daily. We measured and compared the cell cycle of 2D cells and CTCs using propidium iodide. Next, we tested the CTCs and 2D cells with 5 μM vinorelbine, 50 μM gemcitabine, 0.1 μM paclitaxel, or 10 μg/ml etoposide and measured total live cells after 2 days of culture. All analysis was performed using PRISM software and Student’s t-test was used to compare the significance of variance.

      Results:
      Cell cycle analysis of CTCs from a 4D model seeded with H1299 cells showed a significantly higher population of cells in G0/G1, resting cell cycle phase, than in respective 2D cells (65% vs 49%, p<0.01). Furthermore, our results showed a significant decrease in 2D cells upon treatment with all chemotherapeutic drugs. There was a significantly smaller number of 2D cells in the treatment group when treated with gemcitabine (p<0.0001), paclitaxel (p=0.01) and etoposide (p<0.0001) and vinorelbine (p=0.006) than in the control group. On the other hand, there was no significant effect of drugs on the total live CTCs from the 4D model with H1299 that were treated with all four drugs on a 96-well plate as compared to the untreated control group. For H1299 CTCs, there was no significant difference in the number of cells when treated with gemcitabine (p=0.38), paclitaxel (p=0.828), and etoposide (p=0.162), while there were significantly more CTCs with the vinorelbine treatment (p=0.04) compared to the control group.

      Conclusion:
      Overall, our results show that CTCs from the 4D model are different from parental 2D cells that were placed in the 4D model. These CTCs enter the G0/G1 phase, which may confer resistance to chemotherapeutic agents that are cell-cycle-dependent in efficacy. Further characterization of the CTCs from the model may provide the mechanism of the cell cycle arrest and chemotherapy resistance.

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