Cisplatin-Resistant Lung Adenocarcinoma Cells Exhibit Increased Proangiogenic Capacity in a Microphysiological Model of Tumor Neovascularization.

Carcinomas commonly recur and progress rapidly after a period of remission following platinum-based therapy. This clinical scenario suggests that surviving drug-resistant tumor cells are dormant or slow-cycling before re-entering a rapid growth phase. Remodeling of the recurrent tumor microenvironment (TME) contributes to high rates of metastasis, but little is known about differences in TME remodeling before therapy and after recurrence. This study explores selection for cisplatin-resistant subpopulations of A549 lung adenocarcinoma cells in culture to derive populations for modeling features of the recurrent TME. A cisplatin dose of 25 μM killed approximately 80% of the cells while sparing enough cells to allow re-expansion of sufficient cell numbers for downstream experimentation. Expanded cisplatin-resistant derivatives (Cis-R A549) exhibited features of mesenchymal transition (EMT) such as cellular hypertrophy, loss of cell-cell contacts, and upregulation of alpha-smooth muscle actin mRNA. In 3D culture, Cis-R A549 spheroids were loosely aggregated and dysmorphic in comparison to the compact and spherical parent A549 spheroids. The Ki67 index of Cis-R A549 in 2D and 3D spheroid culture was markedly lower than that of parent A549, suggesting a state of pseudo-dormancy with slow cycling. Cis-R A549 upregulated multiple genes associated with the evolution of a more aggressive TME and displayed significantly increased proangiogenic capacity in a microphysiological model of tumor angiogenesis. This study establishes a methodological framework for engineering the recurrent TME with drug-resistant cancer cell line derivatives selected via high-dose exposure in culture. Increased angiogenesis induced by Cis-R A549 suggests that anti-angiogenic therapy may be more beneficial in the setting of recurrent disease following first-line therapies.