AIMThe metastatic ability of a Dunning R-3327 rat prostate cancer subline (AT6.3) was suppressed by the introduction of human chromosome 10, when these hybrid cancer cells were injected subcutaneously into nude mice (Nihei et al., Genes Chromosomes Cancer 14:112-119, 1995). The present study was undertaken to clarify which step of metastasis was suppressed in the human chromosome 10-containing microcell hybrids (AT 6.3-10 clones).

METHODSGelatin zymography, an in vitro invasion assay using a Boyden chamber and an intravenous metastasis assay involving the injection of hybrid cells into nude mice were performed.

RESULTSGelatin zymography revealed that AT6.3-10 microcell hybrid clones expressed the 72 kD type IV collagenase (MMP-2) at an almost equal level as control microcell hybrid clones. Both the invasiveness as measured by the invasion assay and the number of lung metastases as measured by the intravenous metastasis assay of AT6.3-10 hybrid clones were significantly less than those of the AT6.3 parental clone.

CONCLUSIONThe human chromosome 10 suppresses both the local invasion and the metastatic process after entry into the blood circulation of rat prostate cancer. This decrease in local-invasive ability does not seem to require a decrease in MMP-2 activity.

Animals ; Animals, Genetically Modified ; Cell Division ; Chromosomes, Human, Pair 10 ; Gelatin ; analysis ; Humans ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Neoplasm Invasiveness ; Neoplasm Metastasis ; genetics ; Prostatic Neoplasms ; genetics ; pathology ; Rats ; Skin Neoplasms ; genetics ; pathology ; secondary ; Tumor Cells, Cultured

Androgens play a central role in prostate cancer pathogenesis, and hence most of the patients respond to androgen deprivation therapies. However, patients tend to relapse with aggressive prostate cancer, which has been termed as hormone refractory. To identify the proteins that mediate progression to the hormone-refractory state, we used protein-chip technology for mass profiling of patients' sera. This study included 16 patients with metastatic hormone-refractory prostate cancer who were initially treated with androgen deprivation therapy. Serum samples were collected from each patient at five time points: point A, pre-treatment; point B, at the nadir of the prostate-specific antigen (PSA) level; point C, PSA failure; point D, the early hormone-refractory phase; and point E, the late hormone-refractory phase. Using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry, we performed protein mass profiling of the patients' sera and identified a 6 640-Da peak that increased with disease progression. Target proteins were partially purified, and by amino acid sequencing the peak was identified as a fragment of apolipoprotein C-I (ApoC-I). Serum ApoC-I protein levels increased with disease progression. On immunohistochemical analysis, the ApoC-I protein was found localized to the cytoplasm of the hormone-refractory cancer cells. In this study, we showed an increase in serum ApoC-I protein levels in prostate cancer patients during their progression to the hormone-refractory state, which suggests that ApoC-I protein is related to progression of prostate cancer. However, as the exact role of ApoC-I in prostate cancer pathogenesis is unclear, further research is required.
Aged ; Amino Acid Sequence ; Antineoplastic Agents, Hormonal ; therapeutic use ; Apolipoprotein C-I ; analysis ; blood ; isolation & purification ; Blotting, Western ; Cell Line ; Disease Progression ; Drug Resistance, Neoplasm ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Molecular Sequence Data ; Prognosis ; Prostatic Neoplasms ; drug therapy ; metabolism ; Protein Array Analysis ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Aged ; Androgen Antagonists/adverse effects* ; Anticholesteremic Agents/therapeutic use* ; Cholesterol, HDL/blood* ; Cholesterol, LDL/blood* ; Humans ; Hypercholesterolemia/chemically induced* ; Lipids/blood* ; Male ; Middle Aged ; Prostatic Neoplasms/therapy* ; Retrospective Studies ; Testosterone/blood*