Figure 4

Chemoresistant ovarian cancer cells have increased mitochondrial function. (A) Mitochondrial potential of the cells was measured by JC-1 staining. The green fluorescence indicates de-energized mitochondria and the red fluorescence indicates energized mitochondria. Red to green fluorescence intensity ratio indicated increased mitochondrial potential and is represented as a bar graph. The experiment was performed in triplicates and replicated twice. ***p < 0.001, **p < 0.01, chemoresistant cells (C200 and PEO4 compared to respective chemosensitive cells [A2780 and PEO1]). (B) Representative electron microscope pictures of mitochondria. Cells were washed, fixed, embedded in Spurr’s resin and 90 nm sections were placed on 200 mesh copper grids and then examined under Philips Transmission Electron Microscope 208. Mitochondrial count was performed by counting mitochondria per high power field from 15 fields per cell line. **p < 0.01, *p < 0.05 chemoresistant cells (C200 and PEO1 compared to respective chemosensitive cells [A2780 and PEO1]). (C) Palmitate-linked OCR representing fatty acid oxidation. Bovine Serum Albumin (BSA) is the vehicle control for palmitate. ***p < 0.001, **p < 0.01, *p < 0.05 palmitate compared to BSA in respective cell line. ###p < 0.001, resistant cells (C200 and PEO4) compared to sensitive cells (A2780 and PEO1). (D,E) Extracted mRNA from cells was used to synthesize cDNA and expression of mitochondrial biogenesis genes was estimated by RT-PCR. The RT-PCR polymerase chain reaction was ran in triplicates and is representative of 2 individual runs. ***p < 0.001, *p < 0.05 chemoresistant cells (C200 and PEO4 compared to respective chemosensitive cells [A2780 and PEO1]). Abbreviations: DRP1: dynamin-related protein; LONP: Lon protease homolog, mitochondrial; TFAM1: mitochondrial transcription factor A, JC-1: 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimi-dazolylcarbocyanine iodide.