Mapping of metastasis suppressor genes for prostate cancer by microcell-mediated chromosome transfer

Aim:To identify the metastasis suppressor genes for prostate cancer.Methods:A copy of human chromosomeswas introduced into the highly metastatic Dunning R-3327 rat prostate cancer cells by the use of microcell-mediatedchromosome transfer.Relationships between the size of human chromosomes introduced into microcell hybrid clonesand the number of lung metastases produced by the clones were analyzed to determine which part of human chromo-somes contained the metastasis suppressor gene(s)for prostate cancer.To determine portions of human chromosomesintroduced,G-banding chromosomal analysis,fluorescence in sim hybridization analysis,and polymerase chain reac-tion analysis were performed.Results:Each of microcell hybrid clones containing human chromosomes 7,8,10,11,12,or 17 showed decreased ability to metastasize to the lung without any loss of tumorigenicity.This demonstratesthat these human chromosomes contain metastasis suppressor genes for prostate cancer.Spontaneous deletion of portionsof human chromosomes was observed in the human chromosome 7,10,11,12,and 17 studies.In the human chromo-some 8 study,irradiated microcell-mediated chromosome transfer was performed to enrich chromosomal arm deletionsof human chromosome 8.Molecular and cytogenetic analyses of microcell hybrid clones demonstrated that metastasissuppressor genes on human chromosomes were located on 7q21-22,7q31.2-32,8p21-12,10q11-22,11p13-11.2,12p11-q13,12q24-ter,and 17pter-q23.KAII and MKK4/SEKI were identified as metastasis suppressor genes from11p11.2 and 17p12,respectively.Conclusion:This assay system is useful to identify metastasis suppressor gene(s)for prostate cancer.

KAI1/CD82 gene expression in benign prostatic hyperplasia and late-stage prostate cancer in Chinese

Aim: To evaluate KAII/CD82 expression in Chinese patients with benign prostatic hyperplasia (BPH) and late-stage carcinoma of prostate (CaP). Methods: Thirty Chinese patients with benign prostatic hyperplasia and 34 withCaP (adenocarcinoma clinical stage C and D) were analyzed by means of immunohistochemical methods. Results:The KAII/CD82 expression in BPH tissue was all positive, which was uniformly located on the glandular cell mem-brane at the cell-to-cell borders, but KAII/CD82 expression in metastasis CaP tissues was either significantly lower thanthat of BPH or negative, and the immunostaining pattern was not continuous. In late-stage CAP KAII/CD82 expressionwas correlated inversely to the pathological grade ( P < 0.05), but not to clinical stage ( P > 0.05). Conclusion:The authors believe that decreased and negative KAII/CD82 expression in late-stage CaP may be related to tumor pro-gression and metastasis, and appears to be a prognostic marker.

IDENTIFICATION OF A NEW HUMAN nm23 GENE,nm23-H3b

Nm23 is a kind of effective tumor metastasis suppressor genes which included two types in human:nm23-H1 and nm23-H2. Amino acid identity between nm23-H1 and nm23-H2 was 88%.In this study,using a pair of primers to flank the part of coding sequence of nm 23,the 5'-translated sequence was amplified by polymerase chain reaction (PCR) from human normal liver genomic DNA.A 375-base pairs clone was charactertzed,which designated pnm23-H3b.The nm23-H3b nucleotide sequence between 40 bp and 70 bp is different from nm23-H1 and nm23-H2,and other sequences have 86%and 90%identical to nm23-H1 and nm23-H2,respectively.Southern blot containing BglⅡ-digested human liver genomic DNA hybridized to the entire nm23-H3b DNA and showed three bands at 10.5,7.9 and 4.0 Kb.These data demonstrate that the third human nm23 exists possibly.Therefore,nm23 may be considered a family of closely related genes.

The Expression and Significance of KAl1 and Ki67 in Bladder Transitional Cell Carcinoma

OBJECTIVE To explore the expression and significance of the tumor metastatic suppressor gene the KAI1 and Ki67 antigen in bladder transitional cell carcinoma （BTCC）. METHODS Two-stepped immuno-histochemical staining was used to detect the expression of the KAI1 protein and Ki67 antigen. The reverse transcription polymerase chain reaction （RT-PCR） was used to detect the KAI1 mRNA in 54 BTCC specimens and 32 normal bladder counterparts. 13-actin was the internal control. RESULTS The KAI1 protein was mainly expressed on cell membranes at cell-to-cell borders, with uniform and continuous staining in normal bladder transitional epithelium. However, the number of positive-staining cells was greatly decreased in BTCC epithelium, and with an increase in the stage and Grade and appearance of lymph node metastasis the staining was non-uniform and discontinuous. The Ki67 antigen was expressed in the nucleus, and with an increase in the stage and Grade and appearance of lymph node metastasis, the Ki67 expression increased. The Ki67 antigen was negatively related to the expression of KAI1 （P〈0.01）.The expression level of KAI1 mRNA was much greater in normal bladder transitional epithelium compared to BTCC, moreover, with an increase in the Grade, infiltration depth and appearance of lymph node metastasis, the expression of KAI1 mRNA was reduced. CONCLUSION The expression of KAI1 protein may be used as a prognostic marker to indicate the degree of infiltration and metastasis. Measurement of KAI1 and Ki67 expression together may be helpful in evaluating the metastatic potential and prognosis of BTCC patients.