Application

Side Population (SP) Cell Sorting

Side population (SP) cells are typically considered to be stem cells or cells which at least share some of the properties of stem cells. When labeled with the DNA binding dye Hoechst 33342, the efflux pump in SP cells pumps out some of the dye, so that their DNA associated fluorescence is less intense than non-stem cells. This can be confirmed by using drugs like Verapamil or Reserpine which inhibit the efflux pump and cause the fluorescence of stem cells to be equivalent to other cells. (i.e., the side population dots "disappear" on the plot). SP cell groups are thought to include cancer stem cells, suggesting their great potential in cancer research.

• Mouse bone-marrow cells were stained with Hoechst 33342, sorted and analyzed with JSAN, then reanalyzed for SP cells. (Fig. 3 ①, ②)
  
• Human breast carcinoma cells (MCF-7) were stained with Hoechst 33342 and PI, then analyzed with JSAN for SP cells. (Fig.3 ③)

Fig.3: SP analysis and sorting ① The population of SP cells was gated and sorted	② The sorted population was reanalyzed with JSAN. The cell population in the gate above represents SP cells	③ PI negative cell population was gated, and Hoechst 33342 stained cells were analyzed with FL7 and FL8. The cell population in the gate represents SP cells.

JSAN specifications: Laser: 375 nm, 16mW; Detectors: FL7 402-475 nm filter, FL8 655-725 nm filter; Sorting Speed: 5,000 events per sec.