Mutation analysis of the p51 gene and correlation between p53, p73, and p51 expressions in prostatic carcinoma

T-oligo induces apoptosis in advanced prostate cancer cells

Prostate cancer is the most frequently diagnosed malignancy in men. As cancer progresses from an androgen-sensitive stage to hormone-refractory stage, it turns resistant to androgen ablation therapy. At this stage, effective newer therapies that induce apoptosis are needed for treatment of prostate cancer. DNA oligonucleotides homologous to the telomere 3' overhang (T-oligo) induce apoptosis in several human cancer cells. In the present study, we studied the effect of T-oligo on prostate cancer cells. Our studies showed that androgen-independent DU-145 cells are sensitive to T-oligo in terms of inhibition of proliferation. Moreover, T-oligo induced DU-145 cells to undergo apoptosis. Therefore, our results are encouraging for further investigation in the potential application of T-oligo as a novel therapeutic approach for prostate cancer, especially the androgen-independent.

Comprehensive mutational analysis and mRNA isoform quantification of TP63 in normal and neoplastic human prostate cells

BACKGROUND

The role of TP63 in cancer remains controversial since both oncogenic and tumor suppressive actions have been reported. p63 protein is found in the nuclei of basal cells of the normal prostate, yet it is absent in the vast majority of prostate cancer nuclei. Since a complex array of TP63 mRNA transcripts encode polypeptides with distinct functional properties, it is important to determine which forms are expressed in normal and prostate cancer tissue.

METHODS

We used real-time RT-PCR to distinguish TP63 mRNA isoforms in prostate cancer cell lines (n = 7), and samples from prostate cancer patients. We sequenced all TP63 exons from 20 primary tumors, 20 metastases, 28 tumor xenografts, and 7 prostate cancer cell lines.

RESULTS

TP63 mRNA isoforms were present in all tumors, albeit at levels lower than in normal prostate. The most abundant N-terminal variant was DeltaN; the most abundant C-terminal variant was the alpha form. The prostate tumor cell line CWR22Rv1 contained a single G to T substitution in exon 8 that is identical to a dominant-negative DNA binding inactivation mutation occurring in patients with a congenital TP63 deficiency syndrome. One patient tumor contained a somatic mutation in exon 11.

CONCLUSIONS

The pattern of TP63 mRNA expression in normal prostate tissue is retained in reduced amounts in prostate cancer, and a potentially functional TP63 mutation was identified in one prostate tumor. Thus, if TP63 is a prostate cancer gene it likely functions as a tumor suppressor. Further study of the role of TP63 isoforms in regulating stem cell functions of normal and neoplastic prostate epithelial cells is needed. Prostate 69:559-569, 2009. (c) 2009 Wiley-Liss, Inc.

Ser217Leu polymorphism of the HPC2/ELAC2 gene associated with prostatic cancer risk in Japanese men

The HPC2/ELAC2 gene may be associated with hereditary/familial prostate cancer (PCa). Two common missense variants (Ser217Leu and Ala541Thr) have been reported in the gene. We performed mutational, allelotyping and expression analyses and a molecular epidemiological study to clarify the relations between this gene and prostatic diseases, including PCa and benign prostatic hyperplasia (BPH) in Japanese men. We screened for mutations in 109 patients with PCa including 11 patients from 1 hereditary and 9 familial PCa. Loss of heterozygosity and expression were analyzed. An epidemiological study was done in sporadic PCa (n=98) and BPH (n=143) using 1 novel (Ser627Leu) and 2 previously described polymorphisms of the HPC2/ELAC2 gene. Somatic or germline mutations were not confirmed in any cases of PCa. Loss of heterozygosity at 2 microsatellites, D17S1289 and D17S520, was detected in 1 of 38 and 1 of 35 cases, respectively. Expression analysis revealed decreased or absent mRNA expression in 6 of 38 tumors. Epidemiologic analysis showed that a Leu allele at codon 217 was significantly more frequent in patients with PCa than in controls (10.2% vs. 3.5%, odds ratio = 3.11; 95% confidence interval, 1.22-7.90). At codon 541, all patients with PCa or BPH and all control subjects had the Ala/Ala genotype. At codon 627, the incidence of the Leu variant was slightly, but not significantly, higher in patients with BPH than in controls (7.0% vs. 2.8%, odds ratio = 2.59, 95% confidence interval, 0.94-7.13, not statistically significant). We concluded that germline/somatic mutations of HPC2/ELAC2 are uncommon in PCa. Similarly, allelic imbalances at the gene locus and changes in expression are rare. Although no difference in allele frequency at Ser217Leu between patients with PCa and controls has been reported in a Western population, this polymorphism is a potential indicator of PCa risk in Japanese men and it should be examined in other ethnic groups.