Yoshihiko Hirao

MN/CA IX/G250 as a potential target for immunotherapy of renal cell carcinomas

The monoclonal antibody G250 (mAbG250) raised against a human renal cell carcinoma (RCC) has been shown to react with a large number of RCCs. Recently, G250 antigen was isolated and found to be homologous to the MN/CA9 gene originally identified in HeLa cells. To determine whether G250 antigen (MN/CA IX/G250) could be a potential therapeutic target and a tumour marker, a total of 147 cases of RCC were investigated immunohistochemically as well as by reverse transcriptase polymerase chain reaction (RT-PCR) analysis. In addition, total RNAs extracted from patients’ peripheral blood samples were analysed for MN/CA9/G250 mRNA signals. Immunohistochemistry demonstrated strong expression in 128/147 (87.1%) of RCCs, in contrast to the lack of expression observed in normal tissues. RT-PCR analyses of frozen specimens resulted in the clear detection of MN/CA9/G250 mRNA signals in 137/147 (93.2%), and despite subtle differences the results were almost identical to those for immunohistochemistry. Although high-grade and -stage tumours exhibited significantly lower expression than low-grade and -stage tumours, a large proportion of tumours expressed MN/G250 protein as well as mRNA. RT-PCR analysis of patients’ blood samples revealed the presence of circulating MN/CA9/G250 expressing cells. These findings suggest that this antigen may be a potential therapeutic target as well as diagnostic marker for RCCs.

Combined Androgen Blockade With Bicalutamide for Advanced Prostate Cancer: Long-Term Follow-Up of a Phase 3, Double-Blind, Randomized Study for Survival

A previously reported, double‐blind, randomized, multicenter phase 3 trial in 205 patients with stage C/D prostate cancer compared combined androgen blockade (CAB) with luteinizing hormone‐releasing hormone agonist (LHRH‐A) plus bicalutamide 80 mg versus LHRH‐A plus bicalutamide‐matching placebo (LHRH‐A monotherapy). The analysis at a median follow‐up of 2.4 years indicated that CAB significantly (P < .001) prolonged the time to progression and the time to treatment failure. In the current report, survival data from a long‐term follow‐up (median, 5.2 years) were analyzed.

Immunohistochemical Analysis of Midkine Expression in Human Prostate Carcinoma

Midkine (MK) is a growth/differentiation factor frequently expressed at high levels in some types of human malignancies. To investigate whether MK is a useful marker in prostate carcinogenesis, immunohistochemical analysis was performed on samples of both latent and clinical prostate cancers of various stages, as well as on specimens of normal gland and prostatic intraepithelial neoplasia (PIN). Of the 80 clinical cancers examined, 69 specimens (86.3%) were immunoreactive for MK, with metastatic lesions generally showing higher expression than the corresponding primaries; normal prostate tissues were negative or showed only weak staining. Midkine was also detected in 12 of 15 latent cancers (80%) and in 12 of 16 cases of PIN (75%). In sections of whole prostate, MK showed variable expression through tumorous sections, probably in reflection of heterogeneous cell populations. The results demonstrate the possible value of MK as a marker for early and latent disease, as well as for more advanced clinical stages of prostate cancer.

A Phase I Trial of Vaccination of CA9-Derived Peptides for HLA-A24-Positive Patients with Cytokine-Refractory Metastatic Renal Cell Carcinoma

Purpose: A phase I peptide vaccination trial was done in patients with progressive cytokine-refractory metastatic renal cell carcinoma (RCC) to assess both the toxicity and capability to induce immune responses of three peptides (CA9p219-227, p288-296, and p323-331) derived from CA9, a tumor-associated antigen ubiquitously expressed in RCC. Experimental Design: Twenty-three patients positive for human leukocyte antigen (HLA)-A24 with histologically confirmed RCC were enrolled. Eligibility included progressive disease after standard cytokine therapy with interleukin-2 and/or IFN-α. Patients were vaccinated s.c. with the three peptides emulsified in incomplete Freunds adjuvant at 2-week intervals. Pre- and post-vaccination blood samples were obtained for toxicity assessment and immunologic studies. Patients were monitored for clinical responses on a 3-monthly basis. Results: Vaccinations were well tolerated without any major adverse event. Most of the patients developed peptide-specific CTLs and/or immunoglobulin G reactive to the peptides after the 6th or 9th vaccination, followed by a gradual increase in both CTL frequency and levels of peptide-reactive serum IgG. Three patients with multiple lung metastases showed partial responses with disappearance and shrinking of metastatic lesions. Additionally, stable disease for >6 months was observed in six patients (median duration, 12.2 months). Moreover, the median survival time of all patients who were progressive at trial enrollment after failing immunotherapy was 21.0 months (5-35 months). Conclusions: These results suggest that vaccination of these peptides is safe and recommended for further trials for HLA-A24-positive metastatic RCC patients.

E-cadherin and α -, β - and γ -catenin expression in prostate cancers: correlation with tumour invasion

SummaryThe E-cadherin–catenin complex plays an important role in establishing and maintaining intercellular connections and morphogenesis and reduced expression of its constituent molecules is associated with invasion and metastasis. In the present study, we examined E-cadherin and α-, β- and γ-catenin levels in tumour tissues obtained by radical prostatectomy in order to investigate the relationship with histopathological tumour invasion. Immunohistochemical findings for 45 prostate cancer specimens demonstrated aberrant expression of each molecule to be associated with dedifferentiation and, in addition, alteration of staining patterns for the three types of catenin was significantly correlated with capsular but not lymphatic or vascular invasion. The data thus suggest that three types of catenin may be useful predictive markers for biological aggressiveness of prostate cancer.

Hypomethylation of the MN/CA9 promoter and upregulated MN/CA9 expression in human renal cell carcinoma

MN/CA9 is a cancer-related gene, frequently activated in human renal cell carcinomas (RCCs). To reveal the activation mechanism, we investigated the relationship between methylation status of the MN/CA9 promoter region and gene expression using 13 human RCCs, and examined the effect of in vitro CpG methylation on the MN/CA9 promoter activity using a human RCC cell line (SK-RC-44), expressing MN/CA9. MN/CA9 expression was evaluated by RT-PCR and observed in 10 of 13 RCCs (77%). A total of 9 out of 10 MN/CA9 -positive RCCs (90%) contained clear cell components. Methylation status of 6 CpGs in the MN/CA9 promoter region was decided by using the bisulfite genomic sequencing protocol. Out of 13 RCCs 9 (69%) showed partial hypomethylation of the CpG at –74 bp, while the other 4 RCCs and 3 normal kidney tissue samples showed complete methylation. Hypomethylation of the CpG at –74 bp was strongly correlated with MN/CA9 expression. Luciferase assay revealed that the MN/CA9 promoter activity was strongly suppressed by methylation of the CpG at –74 bp. These findings suggest that hypomethylation of the CpG at –74 bp in the MN/CA9 promoter region might play an important role in this gene activation of human RCC.

Efficacy of primary hormone therapy for localized or locally advanced prostate cancer: results of a 10‐year follow‐up

To evaluate the efficacy of primary hormone therapy for localized or locally advanced prostate cancer, by analysing the 10‐year survival rates for men with localized or locally advanced prostate cancer treated with primary hormone therapy or prostatectomy.

1-tert-Butyl-3-[6-(3,5-dimethoxy-phenyl)-2-(4-diethylamino-butylamino)-pyrido[2,3-d]pyrimidin-7-yl]-urea (PD173074), a Selective Tyrosine Kinase Inhibitor of Fibroblast Growth Factor Receptor-3 (FGFR3), Inhibits Cell Proliferation of Bladder Cancer Carrying the FGFR3 Gene Mutation along with Up-Regulation of p27/Kip1 and G1/G0 Arrest

Activating mutation of the fibroblast growth factor receptor-3 (FGFR3) gene is known as a key molecular event in both oncogenesis and cell proliferation of low-grade noninvasive human bladder urothelial carcinoma (UC), which is characterized by frequent intravesical recurrence. In this study, we investigated the antitumor potentiality of 1-tert-butyl-3-[6-(3,5-dimethoxy-phenyl)-2-(4-diethylamino-butylamino)-pyrido[2,3-d]pyrimidin-7-yl]-urea (PD173074), a small-molecule FGFR3-selective tyrosine kinase inhibitor (TKI), as a therapeutic modality using eight UC cell lines. In our in vitro cell proliferation assay, PD173074 suppressed cell proliferation remarkably in two cell lines, namely, UM-UC-14 and MGHU3, which expressed mutated FGFR3 protein. In contrast, the other six cell lines expressing wild-type FGFR3 or without FGFR3 expression were resistant to PD173074 treatment. Cell cycle analysis revealed the growth inhibitory effect of PD173074 was associated with arrest at G1-S transition in a dose-depending manner. Furthermore, we observed an inverse relationship between Ki-67 and p27/Kip1 expression after PD173074 treatment, suggesting that up-regulation of p27 recruited UC cells harboring activating FGFR3 mutations in G1 that was analogous with the other receptor TKIs acting on the epidermal growth factor receptors. In the mouse xenograft models using subcutaneously transplanted UM-UC-14 and MGHU3, orally administered PD173074 suppressed tumor growth and induced apoptotic changes comparable with the results of our in vitro assay. These findings elucidated the effectiveness of molecular targeted approach for bladder UC harboring FGFR3 mutations and the potential utility to decrease the intravesical recurrence of nonmuscle invasive bladder UC after transurethral surgical resection.

Environmental factors promoting bladder cancer.

Purpose of review To understand the molecular mechanisms of bladder carcinogenesis in relation to environmental carcinogens in order to provide a given population with a preventive value of bladder cancer. Recent findings Cigarette smoking, aromatic amines contained in dyes, chronic inflammation due to infection such as schistosomiasis, anticancer drugs, drug abuse of analgesic, and radiation are considered as well known risk factors of bladder cancer. Several environmental factors are supposed to be involved in carcinogenesis, cancer progression, and patients prognosis in bladder cancer. On the basis of the results of recent genetic studies in relation to bladder carcinogenesis, several genetic polymorphisms of detoxification or DNA repair such as N-acetyltransferase 2, glutathione S-transferases, and human 8-oxoguanine DNA glycosylase 1 give us important information in relation to environmental risk factors and ethnic differences for predicting the prognosis of patients with bladder cancer. Summary Prevention of environmental carcinogens is important from the viewpoint of the social and clinical problems since elucidation of the correlation between epidemiologic and genetic phenomenon enable us to improve the life expectancy and quality of life of bladder cancer patients.

Loss of blood group A antigen expression in bladder cancer caused by allelic loss and/or methylation of the ABO gene

Loss of ABO blood group antigen expression has been reported in transitional cell carcinoma (TCC) of the bladder. Synthesis of the ABO blood group antigen was genetically determined by allelic variants of the ABO gene assigned on 9q34.1. We analyzed loss of heterozygosity (LOH) and promoter hypermethylation of the ABO gene in TCC and compared them with alterations of A antigen expression in TCC, dysplasia and normal urothelium. A total of 81 samples of TCC of the bladder obtained from transurethral resection (TUR) (n=44) and radical cystectomy (n=37) were examined. Expression of the A antigen was evaluated by immunohistochemical staining (IHC) using anti-A antigen monoclonal antibody. LOH of the ABO gene locus was examined by blunt-end single-strand DNA conformational polymorphism (SSCP) analysis using flouresence-based auto sequencer. Promoter hypermethylation of the ABO gene were examined by bisulfite PCR-SSCP (BiPS) analysis and/or methylation-specific PCR (MSP). Loss of A allele and/or hypermethylation were significantly associated with abnormal expression of the A antigen in cases undergoing TUR (P=0.02) and radical cystectomy (P=0.0005). For the analysis of the concomitant dysplasia in 23 cases with TCC of the bladder, the expression of the A antigen was maintained, regardless of the A allelic loss or methylation status in the tumor. In conclusion, A allelic loss and hypermethylation in the promoter region of the ABO gene showed significant correlation with reduction of A antigen expression in TCC, while the expression of the A antigen is maintained in concomitant dysplasia or normal urothelium, suggesting that loss of the ABO gene and/or its promoter hypermethylation is a specific marker for TCC.