FIGURE 4 from Sigma1 Regulates Lipid Droplet–mediated Redox Homeostasis Required for Prostate Cancer Proliferation

Abstract

<p>LDs as buffers of DHT induced ROS and DHT promotes ROS homeostasis. <b>A,</b> Confocal micrograph showing HCS LipidTox stained LDs in LNCaP cells cultured in CSS containing medium for 3 days and treated with DMSO (vehicle) and 1 nmol/L DHT alone or combined with 2.5 mmol/L NAC for 3 days. <b>B,</b> LD quantification of LNCaP cells from A. Data represent LDs per cell and error bars represent SEM. *, <i>P</i> < 0.05; **, <i>P</i> < 0.01; ***, <i>P</i> < 0.001; ****, <i>P</i> < 0.0001. <b>C,</b> Quantification of ROS, detected with CM-H<sub>2</sub>DCFDA in LNCaP treated as described above in A. Data are presented as mean ± SEM from at least three independent determinations. *, <i>P</i> < 0.05; **, <i>P</i> < 0.01; ***, <i>P</i> < 0.001; ****, <i>P</i> < 0.0001. <b>D,</b> Illustration of concept that DHT initially induces ROS to trigger proliferation (1 day of DHT), and subsequently decreases intracellular ROS levels. LD accumulation is observed as DHT decreases ROS levels. <b>E,</b> Quantification of ROS in control (#1) or Sigma1 shRNA (#5) transduced LNCaP cells treated as described above in A. Each datapoint represents mean CM-H<sub>2</sub>DCFDA signal per cell from three fields in three independent wells. <b>F,</b> Redox balance. Total GSH levels and ratio of GSH-to-GSSG measured in nonspecific control shRNA (ns) and in Sigma1 shRNA (#5) transduced LNCaP cells treated as described above in A.</p>