Human Prostate Cancer in a Clinically Relevant Xenograft Mouse Model: Identification of β(1,6)-Branched Oligosaccharides as a Marker of Tumor Progression

Abstract

Purpose: To establish xenograft mouse models of metastatic and nonmetastatic human prostate cancer and to apply these models to the search for aberrant glycosylation patterns associated with tumor progression in vivo and in patients.Experimental Design: Prostate cancer cells (LNCaP, PC-3, LuCaP 23.1, and DU-145) were xenografted subcutaneously into immunodeficient pfpÀ/À mice. Tumor growth and metastasis formation were quantified and as altered glycosylation patterns have been associated with metastasis formation in several other malignancies, prostate cancer cells were profiled by a quantitative real-time PCR (qRT-PCR) glycosylation array and compared with normal human prostate cells. The activity of upregulated glycosyltransferases was analyzed by their sugar residues end products using lectin histochemistry on primary tumors and metastases in the animal experiments and on 2,085 clinical samples.Results: PC-3 cells produced the largest number of spontaneous lung metastases, followed by LNCaP and LuCaP 23.1, whereas DU-145 was nonmetastatic. qRT-PCR revealed an upregulation of b1,6-Nacetylglucosaminyltransferase-5b (Mgat5b) in all prostate cancer cell lines. Mgat5b products [b(1,6)-branched oligosaccharides] were predominantly detectable in metastatic xenografts as shown by increased binding of Phaseolus vulgaris leukoagglutinin (PHA-L). The percentage of prostate cancer patients who were PHA-L positive was 86.5. PHA-L intensity correlated with serum prostate-specific antigen and a cytoplasmic staining negatively affected disease-free survival.Conclusion: We show a novel xenograft mouse model for human prostate cancer respecting the complete metastatic cascade. Specific glycosylation patterns reveal Mgat5b products as relevant markers of both metastatic competence in mice and disease-free survival in patients. This is the first description of Mgat5b in prostate cancer indicating a significant biologic importance of b(1,6)-branched oligosaccharides for prostate cancer progression.

Aberrant Presentation of HPA-Reactive Carbohydrates Implies Selectin-Independent Metastasis Formation in Human Prostate Cancer

“…In prostate cancer, we recently established spontaneous metastasis xenograft models and identified abnormally presented b (1, 6) branched oligosaccharides as a marker of metastatic behavior in vivo and elevated prostate specific antigen (PSA) values in patients (22). The impact of HPAand selectin-binding sites for metastasis formation and patient prognosis in prostate cancer, however, has so far not been analyzed in detail.…”

“…RNA isolation and cDNA synthesis from cell culture grown PC-3, DU-145, VCaP, and PPEC was performed as described (22); expression of glycosyltransferases was assessed using the Human Glycosylation RT 2 Profiler PCR array including 84 glycosyltransferase and glycosidase genes (Qiagen). All arrays were repeated twice with independently isolated RNAs.…”

“…different human adenocarcinomas (2,(6)(7)(8)(9)(10). Briefly, tissue sections were treated overnight with xylol, deparaffinized, and pretreated with 0.1% trypsin (obtained as trypsin powder from Biochrom, substance activity 1512 USP U/mg) in lectin buffer for 15 minutes at 37 C. Afterward, sections were incubated with biotinylated HPA (Sigma) and stained as described before (22). Again, 100 mmol/L DGalNAc was used for inhibition of HPA on parallel sections.…”

“…Male Pfp/Rag2 À/À double-knockout mice (8-12 weeks, 20-25 g) from Taconic were used as described (22).…”

“…G08/75). PC-3 and DU-145 cells were xenotransplanted as described (22). This study firstly describes the use of VCaP cells as a suitable model of metastatic prostate cancer.…”