Poster Presentation NSW State Cancer Conference 2023

Repurposing pirfenidone in combination with temozolomide for the treatment of glioblastoma (#150)

Mahsa MV Vaez Zadeh 1 , Preeti PM Manandhar 2 , Marina MS Santiago 3 , Seong Beom CA Ahn 4 , Benjamin BH Heng 5 , Anna AG Guller 6
  1. Medical School , Macquarie University, Sydney, New South Wales, Australia
  2. Medical School , Macquarie University, Sydney, New South Wales, Australia
  3. Medical School , Macquarie University, Sydney, New South Wales, Australia
  4. Medical School , Macquarie University, Sydney, New South Wales, Australia
  5. Medical School , Macquarie University, Sydney, New South Wales, Australia
  6. Medical School , Macquarie University, Sydney, New South Wales, Australia

Glioblastoma (GB) is a malignant astrocytoma, with the 5-year survival rate close to zero due to limited treatment option. One of the possible strategies that may help to improve survival outcomes, is by repurposing an approved drug to combine with the standard treatment of temozolomide (TMZ) that could target cancer-associated pathways of GB that escape radio- and chemotherapy. In this study, we explored the effect of a repurposed anti-scarring drug pirfenidone (PF) in combination with TMZ for GB treatment using a 3D and 2D in vitro tumour model.

Uniform spheroids of U87 and U251 GB linear human cells were formed using a micro-moulded 3D petri dishes prepared from gelled agarose. These spheroids were treated with different concentrations of TMZ and PF for a duration of 3 weeks. The effect of the drugs on tumour growth was carried out by measuring the spheroids’ diameters over the course of the treatments. Monolayer (2D) culture using the same cells and treatment was also be carried out in parallel as a control. The effect of the drug combination on cell cycle and signalling pathway were assessed using flow cytometry and mass spectrometry respectively.

The results revealed strong synergistic effect of TMZ and PF in 2D cultures of U87 and U251 cells. In U87 spheroids, IC50 were achieved at 10 μM TMZ and 3000 μM PF concentrations after 3 weeks incubation with individual drugs. In U251, there were no statistically significant effects of the drugs on spheroid size over 3 weeks. However, the cell cycle analysis revealed that TMZ caused cell growth arrest in S and G2 phase in both U87 and U251 grown in 2D while PF showed no statistically significant effects in U87 cell cycle.

In conclusion, PF significantly inhibited the growth of U87 3D spheroids and did not affect the size of U251 spheroids. Cell cycle analysis and proteomic analysis are being performed to test the effect of combined TMZ and PF and the mechanisms of their effects.