Selective Modulation of Endoplasmic Reticulum Stress Markers in Prostate Cancer Cells by a Standardized Mangosteen Fruit Extract
Figure 4
Mangosteen fruit extract (MFE) up-regulated endoplasmic reticulum (ER) stress proteins and chaperones in prostate cancer cells.
22Rv1 and LNCaP cells were treated with increasing doses of MFE or α-Mangostin for 24 hr. Cell lysates were prepared and subjected to western blot for detecting the expression of critical ER stress proteins. [A], Expression of ER stress proteins in increasing doses of MFE-treated 22Rv1 and LNCaP cells. [B], Cleaved caspase-4 levels in increasing doses of MFE-treated 22Rv1 and LNCaP cells. [C], Expression of multiple ER chaperones in increasing doses of MFE-treated 22Rv1 and LNCaP cells. Beta-actin was used as a loading control. These results are representatives from three independent experiments. [D], Upper panel, schematic diagram of XBP-1 splicing during ER stress. Lower panel, agarose gel pictures of RT-PCR products. 22Rv1 and LNCaP cells were treated with 15 µg/ml MFE for 24 hr. Total RNA was extracted and subjected to RT-PCR. XBP-1primers spanning the spliced sequence were used. RT-PCR products were run on a 2% agarose gel. GAPDH was used as a control.