OBJECTIVEWe previously showed that introduction of a normal, neomycin-tagged human chromosome 8 reduced the metastatic capacity of C5F rat liver cancer cell line, which had high metastatic potential without affecting tumorigenicity, suggesting the presence of one or more metastasis suppressor genes encoded on human chromosome 8. We proceeded to define further the region harboring the metastasis suppressor gene(s) and to determine the random loss of human chromosome 8 by PCR amplification of sequence tag site (STS) markers.

METHODSThe national Center for Biotechnology Information (NCBI) databases were used as references of the relative genetic distances of the STS markers. C5F genomic DNA and A9/neo8 genomic DNA were used as negative and positive controls for chromosome 8 amplification, respectively. Genomic DNA was isolated and quantified from cultured hybrid clones (A9/C5F-1 and A9/C5F-2 microcell hybrid clones served as metastasis-unsuppressed groups; A9/C5F-4, A9/C5F-8 and A9/C5F-10 microcell hybrid clones served as metastasis suppressed groups). STS-PCR products were separated by electrophoresis through 2% agarose gel.

RESULTSMetastasis-suppressed microcell hybrid clones (A9/C5F-4, A9/C5F-8 and A9/C5F-10) conserved STS markers between D8S542 --> D8S1973 (8p21.1-23.1). In contrast, metastasis-unsuppressed clones (A9/C5F-1 and A9/C5F-2) lacked several markers in this region. In attempts to refine the region retained in the microcell suppressed clones, more densely spaced STS markers in the human chromosome 8p21.1-23.1 were used. We found that the metastasis-suppressed clones retained 18cM region between D8S542 and D8S1973 (8P21.1-23.1), where as the metastasis-unsuppressed clones lacked the region.

CONCLUSIONOur results suggest that a metastasis suppressor gene is located within the interval between D8S542 and D8S1973 on human chromosome 8p21.1-23.1.