In vivo isolation of circulating tumor cells in prostate cancer patients by a medical device

e22055

Background: CTCs are discussed as a prognostic and stratification biomarker, and may help to assess the treatment efficacy. The aim was to demonstrate proof of concept of in vivo CTC isolation in Prostate cancer patients (PCa). Methods: A medical device (CellCollector) was inserted in a cubital vein for 30 minutes. The interaction of target CTCs with the CellCollector was mediated by antibodies to the epithelial cell adhesion molecule (EpCAM). To confirm binding of CTCs to the wire, immunohistochemical staining against Cytokeratin and CD45 was performed. There were 226 applications of the device in 16 metastasized PCa (PCa-m) with up to 8 wire applications per patient, 24 localized PCa (PCa-l) with up to 3 wire applications per patient as well as 19 men with benign prostate hypertrophy (BPH) and 21 women as control group with only one wire application. CTC counts from 22 PCa patients with 58 applications were directly compared to the CellSearch technology. Results: We obtained in vivo isolation of CTCs in 73 of 98 applications to PCa patients (74.5 %). The sensitivity for metastasized PCa was (86.2%) and for local PCa (57.5%), respectively. Follow up data of one patient with PCa-m: 2009 diagnosed PCa with multiple metastases. 2 years later PSA of 11.2ng/mL and 25 CTCs. After transurethral resection and removal of a brain metastasis, CTCs decreased to 20 cells with no effect on PSA levels. 4 months later we observed 187 CTCs and a PSA level of 76ng/mL, which was correlated with the patient condition. In PCa-l patients we observed prior radical prostatectomy (n=18) and 6 (n=15) and 12 (n=7) months after surgery CTC numbers on average of 18.2, 2.8 and 1.4, respectively. In the direct comparison of the CellCollector and CellSearch we showed detection rates of 65% (13/20) and 20% (4/20). Conclusions: We demonstrate the use of CTCs besides PSA during therapy adjustment in PCa patients In summary the CTC detection rate of the CellCollector in PCa-m and PCa-l in comparison to the CellSearch method increased by 26% and 45%. Further molecular genetic CTC characterization as well as multiple antibody coating at the CellCollector will assume crucial information for therapy decisions. Clinical trial information: ISRCTN10403616.

[Obesity as a risk factor for prostate cancer: role for adipocytokines and involvement of tyrosine kinase pathway]

PURPOSE

Obesity is considered to be a risk factor for prostate cancer. Mitogenic actions of leptin, an adipocyte-derived hormone in a variety of cancer cell types have been identified. We have investigated the proliferative effects of leptin on human prostate cancer cells and assessed the role of tyrosine kinase signalling in mediating these actions.

MATERIALS AND METHODS

Two human androgen-resistant prostate cancer cell lines and one androgen-sensitive human prostate adenocarcinoma cell line were treated with leptin (5-100 ng / mL) for up to 48 hours. Under serum-free conditions, cell proliferation was measured using an enzyme-linked colorimetric assay. Furthermore, phosphorylation of a downstream component of MAPK (ERK1 / 2) was detected by Western blotting and a specific inhibitor of MAPK (PD98059; 40 microM) was used to evaluate the role of this signalling pathway.

RESULTS

Leptin dose-dependently increased the cell number in both androgen-resistant cell lines after 24 h and 48 h of incubation (percent of control: DU145 = 194.6 +/- 5.9 %, PC-3 = 177.9 +/- 6.8 %; 100 ng / mL leptin; 48 h; p < 0.001). Conversely, leptin's proliferative effect on the androgen-sensitive cell line was less pronounced (percent of control: LNCaP = 112.3 +/- 6.1 %; 100 ng / mL leptin; 48 h). Leptin also caused dose-dependent ERK1 / 2 phosphorylation in both androgen-resistant cell lines. In addition, pre-treatment with PD98059 inhibited these responses and attenuated leptin's mitogenic action.

CONCLUSIONS

Data from this in vitro study suggest an association between obesity-associated hyperleptinemia and an increased risk for prostate cancer. Further investigations are necessary to clarify whether these data have clinical relevance regarding the use as a prognostic marker for predicting the timing of the occurrence of androgen resistency.