Figure 3. Effect of cisplatin treatment on viability and projected area of breast cancer spheroids following cisplatin treatment.

A, B. MCF7 spheroids initiated with 50 cells/drop demonstrated reduced viability in response to cisplatin treatment. However, cisplatin sensitivity was significantly different depending on the method of spheroid manufacture, i.e. spheroids generated on hanging drop or nutator plates were significantly more chemoresistant to cisplatin (17-20% viable in 50 cells/drop; 46-56% viable in 500 cells/drop) compared to spheroids generated on ultra-low attachment plates (10% viable in 50 cells/drop; 24% in 500 cells/drop). Viability within spheroids was measured using alamarblue fluorescence and normalized to untreated control spheroids generated on the same platform. C, D. Morphometry on untreated and cisplatin-treated spheroids indicated a reduction in spheroid projected area with cisplatin treatment. The extent of reduction in projected area was significantly smaller in spheroids from hanging drop arrays or nutator plates, compared to spheroids from ultra-low attachment plates.