3.2. Combinatorial treatment with TMZ and αCT11 does not
increase GBM cell killing.
To test efficacy of Cx43 targeting in combination with TMZ, we first
investigated the effect of αCT11 peptide on drug efficacy.Organoids were treated with combinations of TMZ (0, 10, 100, 1000 µM)
and αCT11 (0, 4, 40, 400 µM) with the drug and media replenished after 4
days. After combinatorial treatment of GBM organoids for 7 days. Cell
viability was assessed using the CellTiter Glo 3D (Promega) assay. The
assay is used to quantify ATP levels in cells and has been previously
verified for studying the drug efficacy of 3D cancer organoids
(Dominijanni et al., 2021). Live/dead staining was used to qualitatively
confirm results from the viability assay. These images can be found inSupplemental Figures 1-3 . The GBM organoids were grouped by
three concentrations of TMZ (10, 100, or 1000 µM) and a control group
(TMZ = 0), and the organoid viability is compared across three
concentrations of αCT11 (4, 40, or 400 µM) and a control group
([αCT11] = 0) in each TMZ subgroup.
The viability of all 3 GBM cell lines decreased as TMZ concentration
increased (Figure 2 ). In A172 and BT169 organoids, there is no
statistically significant difference between cells treated with TMZ
alone and αCT11 (Figure 2A and 2C ). The U87 organoids showed
significantly decreased viability in the TMZ 10 µM + αCT11 4 µM
condition, but in no other condition (Figure 2B ).