Characterization of iPS87, a prostate cancer stem cell-like cell line

Abstract

Prostate cancer affects hundreds of thousands of men and families throughout the world. Although chemotherapy, radiation, surgery, and androgen deprivation therapy are applied, these therapies do not cure metastatic prostate cancer. Patients treated by androgen deprivation often develop castration resistant prostate cancer which is incurable. Novel approaches of treatment are clearly necessary. We have previously shown that prostate cancer originates as a stem cell disease. A prostate cancer patient sample, #87, obtained from prostatectomy surgery, was collected and frozen as single cell suspension. Cancer stem cell cultures were grown, single cell-cloned, and shown to be tumorigenic in SCID mice. However, outside its natural niche, the cultured prostate cancer stem cells lost their tumor-inducing capability and stem cell marker expression after approximately 8 transfers at a 1:3 split ratio. Tumor-inducing activity could be restored by inducing the cells to pluripotency using the method of Yamanaka. Cultures of human prostate-derived normal epithelial cells acquired from commercial sources were similarly induced to pluripotency and these did not acquire a tumor phenotype in vivo. To characterize the iPS87 cell line, cells were stained with antibodies to various markers of stem cells including: ALDH7A1, LGR5, Oct4, Nanog, Sox2, Androgen Receptor, and Retinoid X Receptor. These markers were found to be expressed by iPS87 cells, and the high tumorigenicity in SCID mice of iPS87 was confirmed by histopathology. This research thus characterizes the iPS87 cell line as a cancer-inducing, stem cell-like cell line, which can be used in the development of novel treatments for prostate cancer.

Characterization of FGFR signaling in prostate cancer stem cells and inhibition via TKI treatment

“…As we examined enriched CSC populations from the common cancer cell lines PC3, DU145, and LNCaP by 3D spheroid culture, we concurrently investigated the iPS87 cell line which originated from a PCa biopsy sample [28,29]. This cell line was established by reprogramming primary prostate tumor cells into induced pluripotent stem cells and was shown to possess tumor initiating ability in vivo [29]. iPS87 cells were propagated as previously described [29].…”

“…This cell line was established by reprogramming primary prostate tumor cells into induced pluripotent stem cells and was shown to possess tumor initiating ability in vivo [29]. iPS87 cells were propagated as previously described [29]. Single iPS87 cells detached from the mouse embryonic fibroblast feeder layer after one day, and by 7 days these cells were able to propagate into spheroids ( Figure 7A).…”

“…Additionally, the study aimed to compare different FGFR inhibitors, differing in their specificity and off-target effects. For these studies, we employed a 3D culture system that promotes the proliferation of spheroids using several commonly studied PCa cell lines, together with a patient-derived pluripotent stem cell line iPS87 [29].…”

“…Thus, utilizing patient-derived organoids and iPS-derived organoids (iDOs) have emerged as promising strategies for disease modeling and drug development. In a prior study from our group, iPS-derived cells were obtained from human PCa biopsy samples to produce iPS87 cells [29]; this may provide a useful platform for other researchers to study PCa stem cells with restored tumor initiating properties in vivo. It was hypothesized that iPS87 spheroids may be utilized as iDOs for their characteristics of self-organizing free-floating cell aggregates with higher order tissue complexity.…”

“…In this study, we introduce a novel 3D culture model to investigate whether FGFR signaling is required for cell survival and proliferation of prostate CSCs. We have examined 3D spheroids of common PCa cell lines, PC3, DU145 and LNCaP, and spheroids of patient-derived iPS87 cells, a novel induced pluripotent stem (iPS) cell line [28,29]. Using unique suspension culture conditions without the ectopic addition of growth factors for culturing 3D spheroids, we evaluated the effects of TKIs PD166866, BGJ398, and Dovitinib.…”