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J.N. Mahale
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P3.05 - Poster Session/ Prevention and Tobacco Control (ID 217)
- Event: WCLC 2015
- Type: Poster
- Track: Prevention and Tobacco Control
- Presentations: 1
- Moderators:
- Coordinates: 9/09/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P3.05-011 - Tumour Microenvironment: A Potential Role for Curcumin in Lung Cancer Chemoprevention (ID 140)
09:30 - 09:30 | Author(s): J.N. Mahale
- Abstract
Background:
Recent studies have shown that the tumour microenvironment plays a crucial role in regulating tumor progression and cell migration. This is of particular importance in diseases such as lung cancer, which exhibit dense stroma. Cell-cell interactions and the effect that drugs have upon them can be investigated via use of in vitro 3D organotypic co-culture models. Curcumin, a naturally occurring polyphenol, is reported to exhibit strong anti-inflammatory, antioxidant, anti-proliferative and chemopreventive activity. An organotypic co-culture model representative of a tertiary prevention model system was used to study lung cancer tumour-stroma interactions and to investigate anti-invasive properties of curcumin. Fibroblast-secreted HGF is reported to stimulate invasion and migration of tumour cells by activation of the cMet pathway. In this study we also determined the potential for curcumin to elicit chemopreventive efficacy via disruption of this pro-proliferative c-Met signalling axis.
Methods:
A549 lung adenocarcinoma cells and MRC5 normal human lung fibroblasts were used for the study. For air-interface organotypic co-culture, a gel matrix consisting of matrigel and rat tail collagen was embedded with MRC5 fibroblasts and a combination of A549 and MRC5 fibroblasts seeded on to the gel. The gel was then placed onto a metal grid in a 6-well plate. Curcumin-containing media was added to the well so that it just touched the bottom of the gel. After 12 days, gels were processed for formalin fixation and paraffin embedding (FFPE). The objectives were as follows: i) to evaluate invasiveness of A549 cells in the absence of fibroblasts; ii) to determine the effect of differing ratios of A549:fibroblasts on invasion; iii) to determine the effect of curcumin treatment on invasion of A549 cells. For HGF estimation, MRC5 fibroblasts were treated with a single dose of curcumin at concentrations ranging from 0 to 5µM. On day 6, media was collected and analysed for determination of HGF levels using ELISA.
Results:
The IC50 value of curcumin for A549 and MRC5 was found to be 4.7±0.8µM and 1.5±0.3µM respectively. In the absence of MRC5 fibroblasts in co-culture, A549 cells did not invade. Five different ratios of A549:MRC5 (1:5, 1:2, 1:1, 2:1 and 5:1) were used to determine effect on invasion. The 1:5 ratio showed maximum invasion whereas 5:1 showed minimal or no invasion. Organotypics (1:5 ratio) were treated with curcumin concentrations ranging from 0µM to 5µM. Curcumin treatment significantly inhibited invasion of A549 cells by 24.39±8.39% in organotypic co-cultures. HGF ELISA on curcumin treated MRC5 media revealed that curcumin significantly inhibited HGF secretion by 67.87±5.96% when adjusted for cell number, at concentration as low as 0.25µM.
Conclusion:
A549 cells require the presence of fibroblasts to invade in the organotypic co-culture model, and invasive index increases with increasing ratio of fibroblasts. Intervention with curcumin in contact with fibroblasts only, suggested that this is sufficient to inhibit invasion of A549. The potential mechanism for this may be via the ability of curcumin to inhibit paracrine signalling networks between the two cell types, which impinge on the cMet signalling axis.
