Biomedical subjects

Tapio Visakorpi

Publications and source records attributed to Tapio Visakorpi.

At least 19 recordsLinked to original sources

PubMed2006

Cellular changes in prostate cancer cells induced by intermittent androgen suppression.

OBJECTIVES: This study used tumour specimens from a clinical trial on intermittent androgen suppression (IAS) to study the effects of castration on tissue morphology, cell proliferation, apoptosis, and the expression of androgen receptor (AR). METHODS: A total of 113 representative needle biopsy specimens were available from 29 patients for evaluation of the Gleason score as well as Ki-67, cleaved caspase-3, and AR immunostaining. RESULTS: At 6 mo from the beginning of the first androgen withdrawal, cell proliferation activity was significantly (p = 0.002) reduced, whereas no effect on apoptosis was found. A nonsignificant trend to an increase in Gleason score after castration was found. Subsequent cycles of withdrawals had no significant effect on any of the measured parameters. The Gleason score, proliferation activity, and apoptosis rate showed only heterogeneous, nonsignificant changes after the first progression. Strong nuclear AR staining was evident in all cancer specimens. CONCLUSIONS: The findings suggest that the long-term (months) effect of androgen withdrawal on tumour growth is due to the inhibition of proliferation. Because the tumours seem to become resistant to castration at the first cycle of treatment withheld, it is possible that IAS does not postpone the emergence of ablation-resistant tumours. There was no consistent sign of increased proliferation or Gleason score during the treatment, suggesting that the biologic aggressiveness of a particular tumour is defined already at an early stage of disease. The constant nuclear expression of AR in cancer cells indicates that the AR signalling remains active despite of the androgen withdrawal.

Androgen Antagonists↗

PubMed2006

Mutation screening of the androgen receptor promoter and untranslated regions in prostate cancer.

BACKGROUND: Mechanisms, other than gene amplification, leading to overexpression of AR in androgen ablation-resistant prostate cancer remain unknown and could include genetic alterations in the promoter or untranslated regions (UTR) of the AR gene. MATERIALS AND METHODS: DNAs from five prostate cancer cell lines, 19 LuCaP xenografts, 44 clinical tumors, and 36 non-malignant controls were used for screening mutations in the upstream regulatory region, promoter and the 5'- and 3'-UTRs of the AR gene with denaturating high performance liquid chromatography (DHPLC) and sequencing. RESULTS: Ten different sequence variations were found in prostate cancer cell lines and xenografts. However, none of them were recurrent or were found in clinical prostate cancer specimens or in normal controls. CONCLUSIONS: Recurrent mutations in the promoter or UTRs of AR seem to be rare, and thus not likely mechanisms for the increased expression of the gene in the androgen ablation-resistant prostate cancer.

Adenocarcinoma↗

PubMed2006

Genetic aberrations in prostate cancer by microarray analysis.

The aim of this study was to screen genetic as well as expression alterations in prostate cancer. Array comparative genomic hybridization (aCGH) to a 16K cDNA microarray was performed to analyze DNA sequence copy number alterations in 5 prostate cancer cell lines and 13 xenografts. The aCGH confirmed the previously implicated common gains and losses, such as gains at 1q, 7, 8q, 16p and 17q and losses at 2q, 4p/q, 6q, 8p, 13q, 16q, 17p and 18q, which have previously been identified by chromosomal CGH (cCGH). Because of the higher resolution of aCGH, the minimal commonly altered regions were significantly narrowed-down. For example, the gain of 8q was mapped to three independent regions, 8q13.3-q21.11, 8q22.2 and 8q24.13-q24.3. In addition, a novel recurrent gain at 9p13-q21 was identified. The concomitant expression analysis indicated that genome-wide DNA sequence copy number (gene dosage) was significantly associated with the expression level (p < 0.0001). The analyses indicated several individual genes whose expression was associated with the gene copy number. For example, gains of PTK2 and FZD6, were associated with the increased expression, whereas losses of TNFRSF10B (alias DR5) and ITGA4 with decreased expression. In conclusion, the aCGH mapping data will aid in the identification of genes altered in prostate cancer. The combined expression and copy number analysis suggested that even a low-level copy number change may have significant effect on gene expression, and thus on the development of prostate cancer.

Animals↗

PubMed2006

Screening of genetic and expression alterations of SRC1 gene in prostate cancer.

BACKGROUND: Genetic alterations of the SRC1 gene have not been thoroughly studied in prostate cancer. MATERIALS AND METHODS: Five prostate cancer cell lines and 32 xenografts were screened for mutations and gene copy number alterations. Subsequently, frequencies of detected sequence variations were further analyzed in 44 clinical prostate cancers, 6 benign prostate hyperplasias, and 48 normal controls. Finally, the protein expression of SRC1 in 254 clinical prostate tumors was investigated. RESULTS: Three non-recurrent sequence variations, and one single nucleotide polymorphism in the coding region of SRC1, as well as one case of SRC1 gene amplification were found. The protein expression of SRC1 was higher in androgen ablation resistant than untreated prostate carcinomas, but the difference was not statistically significant (P = 0.0796). CONCLUSIONS: Genetic alterations of SRC1 are rare in prostate cancer. The nuclear protein accumulation of SRC1 seems to be mildly increased in androgen ablation resistant prostate cancers. .

Androgen Antagonists↗

PubMed2006

Overexpression of EIF3S3 promotes cancer cell growth.

BACKGROUND: Amplification and overexpression of EIF3S3 gene has been demonstrated in breast and prostate cancer. Here, our goal was to study the effect of EIF3S3 on cell growth. METHODS: The effect of EIF3S3 on growth of NIH 3T3 murine fibroblasts as well as breast (SK-Br-3 and ZR-75-1) and prostate (PC-3 and LNCaP) cancer cell lines was examined by using transfection with inducible pTet-Off system and siRNAs. RESULTS: NIH 3T3 cells with overexpression of EIF3S3 grew significantly faster than cells transfected with empty vector and survived longer when grown in soft agar. The EIF3S3 overexpression was associated with increased fraction of cells in S-phase and with phosphorylation of retinoblastoma (Rb) protein. siRNA treatment inhibited significantly (P = 0.0022) the growth of all breast and prostate cancer cell lines studied. CONCLUSIONS: The results suggest that EIF3S3 regulates cell growth and viability, and that overexpression of the gene may provide growth advantage to the cancer cells.

Animals↗

PubMed2006

The gene for polycomb group protein enhancer of zeste homolog 2 (EZH2) is amplified in late-stage prostate cancer.

Overexpression of the polycomb group protein enhancer of zeste homologue 2 (EZH2) has been found in several malignancies, including prostate cancer, with an aggressive phenotype. Amplification of the gene has previously been demonstrated in several malignancies, but not in prostate cancer. Our goal was to evaluate the gene copy number and expression alterations of EZH2 in prostate cancer. The copy number of EZH2 in cell lines (LNCaP, DU145, PC-3, 22Rv1), xenografts (n = 10), and clinical tumors (n = 191) was studied with fluorescence in situ hybridization. All cell lines had a gain of EZH2. Eight of the ten xenografts showed an increased copy number of the gene, including one case of high-level amplification (>or=5 copies of the gene and EZH2/centromere ratio >or=2). 34/125 (27%) of untreated prostate carcinomas showed increased copy number, but only one case of low-level amplification (>or=5 copies of the gene and EZH2/centromere ratio <2), whereas half (25/46) of the hormone-refractory carcinomas showed increased copy number, including seven cases of low-level amplification and three cases of high-level amplification (P < 0.0001). Expression of EZH2 was significantly (P = 0.0009) higher in hormone-refractory prostate cancer compared with that in benign prostatic hyperplasia or untreated cancer, according to quantitative real-time RT-PCR assay. Also, the expression of EZH2 protein was found to be higher in hormone-refractory tumors than in hormone-naïve tumors by immunohistochemistry. The EZH2 gene amplification was significantly (P < 0.05) associated with increased EZH2 protein expression. The data show that amplification of the EZH2 gene is rare in early prostate cancer, whereas a fraction of late-stage tumors contains the gene amplification leading to the overexpression of the gene, thus indicating the importance of EZH2 in the progression of prostate cancer.

Cell Line, Tumor↗

PubMed2006

Amplification of the urokinase gene and the sensitivity of prostate cancer cells to urokinase inhibitors.

OBJECTIVES: To evaluate the frequency of the urokinase-type plasminogen activator (uPA) gene amplification and the sensitivity of prostate cancer cells to uPA inhibition, as we previously found one hormone-refractory prostate tumour with high-level amplification of the uPA (alias PLAU) gene, and also showed that a uPA inhibitor, amiloride, can effectively reduce the invasion potential of the PC-3 prostate cancer cell line. MATERIALS AND METHODS: Sixty-three locally recurrent hormone-refractory tumours and 78 hormone-refractory metastases from 29 patients who died from prostate cancer were analysed for uPA gene-copy number using fluorescence in situ hybridization. The Matrigel invasion assay was used to study the influence of uPA inhibitors on the invasive potential of prostate cancer cell lines. RESULTS: Of the locally recurrent hormone-refractory tumours, 21% had an increased copy number of uPA, but no high-level amplifications were found; 31% of the metastases had increased copy number and one high-level amplification of the uPA. Matrigel invasion assays with two specific uPA inhibitors, B428 and p-aminobenzamidine, showed that invasion of a prostate cancer cell line containing uPA gene amplification was inhibited by these small-molecule uPA inhibitors, while invasion of prostate cell lines without uPA gene amplification were not. CONCLUSION: These results suggest that selective inhibition of the uPA pathway in individuals whose tumours contain uPA gene amplification may provide therapeutic benefit.

Amiloride↗

PubMed2005

Dual-specificity phosphatase 1 and serum/glucocorticoid-regulated kinase are downregulated in prostate cancer.

Inactivation of tumor suppressor genes through deletion, mutation and epigenetic silencing has been shown to occur in cancer. In our study, we combined DNA demethylation and histone deacetylation inhibition treatments with suppression subtraction hybridization (SSH) and cDNA microarrays to identify potentially epigenetically downregulated genes in PC-3 prostate cancer cell line. We found 11 genes whose expression was upregulated after relieving epigenetic regulation. Expression of 3 genes [dual-specificity phosphatase 1 (DUSP1), serum/glucocorticoid regulated kinase (SGK) and spermidine/spermine N1-acetyltransferase (SAT)] was subsequently studied in clinical sample material using real-time quantitative RT-PCR and immunohistochemistry. The DUSP1 and SGK mRNA expression was lower in hormone-refractory prostate carcinomas compared to benign prostate hyperplasia (BPH) or untreated prostate carcinomas. BPH, normal prostate and high-grade prostate intraepithelial neoplasia (PIN) expressed high levels of DUSP1 and SGK proteins. Ninety-two percent and 48% of the prostate carcinomas showed almost complete lack of DUSP1 and SGK proteins, respectively, indicating common downregulation of these genes. The genomic bisulphite sequencing did not reveal dense hypermethylation in the promoter regions of either DUSP1 or SGK. In conclusion, the data suggest that downregulation of DUSP1 and SGK is an early event and could be important in the tumorigenesis of prostate cancer.

Base Sequence↗

PubMed2005

Androgen receptor modifications in prostate cancer cells upon long-termandrogen ablation and antiandrogen treatment.

To study the mechanisms whereby androgen-dependent tumors relapse in patients undergoing androgen blockade, we developed a novel progression model for prostate cancer. The PC346C cell line, established from a transurethral resection of a primary tumor, expresses wild-type (wt) androgen receptor (AR) and secretes prostate-specific antigen (PSA). Optimal proliferation of PC346C requires androgens and is inhibited by the antiandrogen hydroxyflutamide. Orthotopic injection in the dorsal-lateral prostate of castrated athymic nude mice did not produce tumors, whereas fast tumor growth occurred in sham-operated males. Three androgen-independent sublines were derived from PC346C upon long-term in vitro androgen deprivation: PC346DCC, PC346Flu1 and PC346Flu2. PC346DCC exhibited androgen-insensitive growth, which was not inhibited by flutamide. AR and PSA were detected at very low levels, coinciding with background AR activity in a reporter assay, which suggests that these cells have bypassed the AR pathway. PC346Flu1 and PC346Flu2 were derived by culture in steroid-stripped medium supplemented with hydroxyflutamide. PC346Flu1 strongly upregulated AR expression and showed 10-fold higher AR activation than the parental PC346C. PC346Flu1 proliferation was inhibited in vitro by R1881 at 0.1 nM concentration, consistent with a slower tumor growth rate in intact males than in castrated mice. PC346Flu2 carries the well-known T877A AR mutation, causing the receptor to become activated by diverse nonandrogenic ligands including hydroxyflutamide. Array-based comparative genomic hybridization revealed little change between the various PC346 lines. The common alterations include gain of chromosomes 1, 7 and 8q and loss of 13q, which are frequently found in prostate cancer. In conclusion, by in vitro hormone manipulations of a unique androgen-dependent cell line expressing wtAR, we successfully reproduced common AR modifications observed in hormone-refractory prostate cancer: downregulation, overexpression and mutation.

Androgen Antagonists↗

PubMed2005

Primary cutaneous T-cell lymphomas show a deletion or translocation affecting NAV3, the human UNC-53 homologue.

Multicolor fluorescent in situ hybridization (FISH) was used to identify acquired chromosomal aberrations in 12 patients with mycosis fungoides or Sézary syndrome, the most common forms of primary cutaneous T-cell lymphoma (CTCL). The most frequently affected chromosome was 12, which showed clonal deletions or translocations with a break point in 12q21 or 12q22 in five of seven consecutive Sézary syndrome patients and a clonal monosomy in the sixth patient. The break point of a balanced translocation t(12;18)(q21;q21.2), mapped in the minimal common region of two deletions, fine mapped to 12q2. By locus-specific FISH, the translocation disrupted one gene, NAV3 (POMFIL1), a human homologue of unc-53 in Caenorhabditis elegans. A missense mutation in the remaining NAV3 allele was found in one of six cases with a deletion or translocation. With locus-specific FISH, NAV3 deletions were found in the skin lesions of four of eight (50%) patients with early mycosis fungoides (stages IA-IIA) and in the skin or lymph node of 11 of 13 (85%) patients with advanced mycosis fungoides or Sézary syndrome. Preliminary functional studies with lentiviral small interfering RNA-based NAV3 silencing in Jurkat cells and in primary lymphocytes showed enhanced interleukin 2 expression (but not CD25 expression). Thus, NAV3 may contribute to the growth, differentiation, and apoptosis of CTCL cells as well as to the skewing from Th1-type to Th2-type phenotype during disease progression. NAV3, a novel putative haploinsufficient tumor suppressor gene, is disrupted in most cases of the commonest types of CTCL and may thus provide a new diagnostic tool.

Alleles↗

PubMed2005

Epidermal growth factor receptor domain II, IV, and kinase domain mutations in human solid tumors.

Mutations that may predict response to adenosine 5'-triphosphate (ATP)-mimetic epidermal growth factor receptor (EGFR) inhibitors occur in the EGFR kinase domain in lung adenocarcinomas and bronchioloalveolar carcinomas (BACs). Data on the frequency of EGFR mutations are sparse in other human tumors. Apart from the deletion mutant EGFRvIII, little is known about the frequency of mutations that encode for the EGFR extracellular domains II and IV that participate in receptor dimerization and formation of the tethered (autoinhibited) receptor conformation. We investigated 566 human neoplasms consisting of various histological types for mutations in exons 6, 7 (encode domain II), 14, 15 (domain IV), 18, 19, and 21 (the kinase domain) using denaturing high-performance liquid chromatography (DHPLC). Approximately 4,500 EGFR exons were screened for the presence of a mutation, and samples with an abnormal finding in DHPLC were sequenced. Only one mutation was found in the extracellular domain IV (glioblastoma), and none in domain II. Eight (11%) out of the 40 lung adenocarcinomas, or 33 BACs, investigated had exon 19 or 21 mutation in the kinase domain, but no mutations were found in other tumor types. Most of the lung cancers with mutated EGFR had three to six copies of the mutated gene in fluorescence in situ hybridization. We conclude that mutations of the EGFR kinase domain and the cysteine-rich extracellular domains are infrequent in most types of human cancer apart from lung adenocarcinoma. Mutated EGFR is usually not amplified in lung cancer.

Amino Acid Sequence↗

PubMed2005

CBX7 controls the growth of normal and tumor-derived prostate cells by repressing the Ink4a/Arf locus.

Control of cell proliferation by Polycomb group proteins (PcG) is an important facet of cellular homeostasis and its disruption can promote tumorigenesis. We recently described CBX7 as a novel PcG protein controlling the growth of normal cells. In an attempt to identify a putative role of CBX7 in tumorigenesis, we analysed CBX7 expression in a panel of cancer cell lines and primary tissues. CBX7 was highly expressed in three different prostate cancer cell lines and present at elevated levels in normal prostate. Ablation of CBX7 expression using short hairpin RNAs (shRNA) resulted in upregulation of p16Ink4a and p14Arf in both LNCaP and PC-3 prostate cell lines. CBX7 knockdown caused an impairment of cell growth that was dependent on the status of the p14Arf/p53 and p16Ink4a/Rb pathways in both normal and cancer prostate cells. CBX7 overexpression in LNCaP cells resulted in a slight growth advantage in both androgen-dependent and -independent conditions. Moreover, CBX7 expression cooperated with c-Myc in rendering LNCaP cells insensitive to growth arrest by androgen receptor inhibition. Together, these data suggest that CBX7 represses p16Ink4a and p14Arf expression in normal and tumor-derived prostate cells, affecting their growth depending on the status of the p16Ink4a/Rb and the p14Arf/p53 pathways.

Androgens↗

PubMed2004

Alterations of androgen receptor in prostate cancer.

The significance of androgens in the development of prostate cancer has been known for more than half century. During the last decade, a lot of effort has been put to study the significance of the specific nuclear receptor of the hormone, androgen receptor (AR). It has been suggested that polymorphisms, especially the length of CAG repeat in exon 1 of the gene, are associated with the risk of prostate cancer. However, not all studies have confirmed the association. Most surprisingly, it has now become clear that prostate carcinomas emerging during the androgen withdrawal therapy (i.e. hormone-refractory tumors) are capable of reactivating the AR-mediated signalling despite of the low levels of androgens. In addition, it has been shown that AR gene itself is genetically targeted. One-third of the hormone-refractory prostate carcinomas contains amplification of the gene. In addition, 10-30% of prostate carcinomas treated by antiandrogens acquire point mutation in the AR gene. The genetic alterations in AR indicate that receptor should be considered as putative treatment target. Evidently, the currently available antiandrogens are not capable to abolish the AR-mediated signalling efficiently enough.

Androgen Antagonists↗

PubMed2004

Endometrial K-ras mutations in postmenopausal breast cancer patients treated with adjuvant tamoxifen or toremifene.

PURPOSE: Long-term use of tamoxifen is associated with a two- to threefold increased risk of endometrial cancer in postmenopausal women. Toremifene is another triphenylethylene antiestrogen, which is as effective as tamoxifen in postmenopausal breast cancer. Thus far, its use has not been associated with an increased risk of endometrial cancer. K-ras codon 12 mutations seem to be important in endometrial carcinogenesis, and these mutations have been found in endometrial samples of patients on tamoxifen. The present study was undertaken to investigate if there is any difference in the frequency of endometrial K-ras mutations among patients treated with tamoxifen or toremifene. METHODS: Endometrial samples were taken from 23 postmenopausal breast cancer patients (tamoxifen, n = 11; toremifene, n = 12) before and after 36 months of treatment. DNA was isolated from formalin-fixed paraffin-embedded samples using a routine proteinase K digestion protocol. K-ras mutations in codon 12 were screened using real-time PCR and melting curve analysis in LightCycler equipment. Wild-type PNA oligomer was used to increase the sensitivity of the assay. RESULTS: All baseline samples contained wild-type K-ras, while 10/23 (43%) of the follow-up samples carried a codon 12 mutation. Mutations were identified in 3 of the 11 in the tamoxifen group and in 7 of the 12 in the toremifene group. Seven were transitions (G-->A), and three were transversions (two G-->T, one G-->C). One of the mutations in the toremifene group was associated with a polypoid endometrium. All the other mutations were found in an atrophic (n = 6) or proliferative (n = 3) endometrium. CONCLUSIONS: Both tamoxifen and toremifene induce endometrial K-ras codon 12 mutations. The significance of this finding to endometrial carcinogenesis remains to be elucidated.

Antineoplastic Agents, Hormonal↗

PubMed2004

PrLZ, a novel prostate-specific and androgen-responsive gene of the TPD52 family, amplified in chromosome 8q21.1 and overexpressed in human prostate cancer.

We report a previously unrecognized prostate-specific protein, PrLZ (prostate leucine zipper), a new member of the Tumor Protein D52 (TPD52) family. The gene for PrLZ was localized at chromosome 8q21.1, a locus most frequently amplified in human prostate cancer. Multiple tissue analyses demonstrated PrLZ predominantly in the prostate gland. Although its expression was enhanced by androgens in androgen receptor-expressing cells, PrLZ was detected in all of the human prostate cancer cell lines, regardless of androgen receptor status. Monoclonal anti-PrLZ antibodies were produced and intense immunohistochemical staining of PrLZ was observed in prostate epithelial cells in intraepithelial neoplasia and prostate cancer, whereas lower-level staining was detected in normal and benign epithelial components of the prostate gland. As the only prostate-specific gene identified in the most frequently amplified genomic region in prostate cancer, PrLZ may be the link between chromosome 8q amplification and malignant transformation of the prostate epithelia.

Androgens↗

PubMed2004

Expression of androgen receptor coregulators in prostate cancer.

PURPOSE: The androgen receptor (AR)-mediated signaling pathway seems to be essentially involved in the development and progression of prostate cancer. In vitro studies have shown that altered expression of AR coregulators may significantly modify transcriptional activity of AR, suggesting that these coregulators could also contribute to the progression of prostate cancer. Here, our goal was to assess alterations in the expression of the AR coregulators in prostate cancer in vivo. EXPERIMENTAL DESIGN: The expression of 16 AR coactivators and corepressors (SRC1, beta-catenin, TIF2, PIAS1, PIASx, ARIP4, BRCA1, AIB1, AIB3, CBP, STAT1, NCoR1, AES, cyclin D1, p300, and ARA24) was measured in prostate cancer cell lines, xenografts, and clinical prostate tumor specimens by using real-time quantitative reverse transcription-PCR. In addition, gene copy number of SRC1 was analyzed by fluorescence in situ hybridization. RESULTS: Both AR-positive and AR-negative cell lines and xenografts expressed the coregulators. Most of the coregulators studied were expressed at equal levels in benign prostatic hyperplasia and untreated and hormone-refractory carcinomas. However, the expression of PIAS1 and SRC1 was significantly (P = 0.048 and 0.017, respectively) lower in hormone-refractory prostate tumors than in untreated prostate tumors. No overexpression of the coregulators was found in the clinical material. Paradoxically, the SRC1 gene was found to be amplified and highly expressed in a LuCaP 70 prostate cancer xenograft. CONCLUSIONS: These findings suggest that the decreased expression of PIAS1 and SRC1 could be involved in the progression of prostate cancer. In addition, gene amplification of SRC1 in one of the xenografts implies that, in some tumors, genetic alteration of SRC1 may provide a growth advantage.

Animals↗

PubMed2004

RAD21 and KIAA0196 at 8q24 are amplified and overexpressed in prostate cancer.

To detect genes that are overexpressed in prostate cancer, a subtracted cDNA library was first constructed from the PC-3 cell line and subsequently screened by using cDNA microarray hybridization. Sixty-eight genes were found to be overexpressed (ratio>3) in PC-3. Half of these genes were in chromosomal regions, which, using comparative genomic hybridization, we previously showed to be gained in PC-3. Subsequently, the expression and copy number of selected genes were studied by quantitative RT-PCR and fluorescence in situ hybridization in prostate cancer cell lines, xenografts, and clinical tumor specimens of benign prostate hyperplasia and untreated as well as hormone-refractory prostate carcinomas. Two genes from chromosomal region 8q24-RAD21 and KIAA0196-showed increased expression in clinical prostate carcinomas and were also amplified in 30-40% of xenografts and hormone-refractory tumors. In addition, the expression of KIAA0196 was significantly (P=0.0051) higher in tumors with the gene amplification than in those without it. The data suggest that KIAA0196 and possibly RAD21 are putative target genes for the common amplification of 8q23-24 in prostate cancer.

Blotting, Northern↗

PubMed2004

Mutational analysis of susceptibility genes RNASEL/HPC1, ELAC2/HPC2, and MSR1 in sporadic prostate cancer.

Three putative prostate cancer-susceptibility genes, RNASEL/HPC1 at 1q24, MSR1 at 8p22, and ELAC2/HPC2 at 17p11, have recently been identified. Our objective was to investigate somatic mutations in these genes in sporadic prostate cancer. We analyzed 39 clinical prostate cancer specimens, 10 prostate cancer xenografts (LuCaP series), and 4 prostate cancer cell lines (LNCaP, DU145, PC-3, and MPC-3) for genetic changes using denaturing high-performance liquid chromatography and direct sequencing in order to screen the whole coding regions of RNASEL and MSR1, as well as exons 7 and 17 of ELAC2. The known 471delAAAG truncating mutation was found in the RNASEL gene in cell line LNCaP. The only new missense variation in RNASEL, Gly296Val, was found in cell line DU145, but not in any other samples. RNASEL and ELAC2 also showed the common missense polymorphic changes. A previously reported truncating mutation (Arg293X) was found in MSR1 in the germ line of one individual. Our results indicate that inactivation of the RNASEL, ELAC2, or MSR1 genes by somatic mutation is a rare phenomenon in sporadic prostate cancer.

Animals↗