Published papers

Purpose: There are still few effective therapeutic options for advanced prostate cancer. One of the most troublesome aspects of prostate cancer is that androgen dependent prostate cancer inevitably progresses to highly aggressive, life threatening castration resistant prostate cancer after androgen ablation therapy. To our knowledge it remains unknown how sensitivity to docetaxel changes during progression to more aggressive castration resistant prostate cancer under androgen ablation. Materials and Methods: We investigated sensitivity to docetaxel and phosphorylated Akt status in C4-2 and C4-2AT6 cells established at our institution. Results: C4-2AT6 cells established under androgen ablation conditions for 6 months showed significantly higher resistance to docetaxel than C4-2 cells in vivo and in vitro. Resistance was accompanied by increased phosphorylated Akt. In C4-2AT6 cells phosphorylated Akt activity was significantly up-regulated by docetaxel in a dose dependent manner. After treatment with docetaxel and a phosphatidylinositol 3-kinase/Akt inhibitor the sensitivity of C4-2AT6 cells to docetaxel markedly increased through enhanced apoptotic death. Conclusions: Findings indicated that up-regulation of phosphorylated Akt during androgen ablation and its further activation by docetaxel explains at least in part the resistance to docetaxel and progression to castration resistant prostate cancer under androgen ablation conditions.

A 55-year-old man who had been undergoing hemodialysis for 9 years visited our institution after the sudden onset of severe left flank pain. He presented with hypotension and was admitted immediately because computed tomography (CT) revealed a massive perirenal hematoma. Renal arteriography showed contrast media leakage at the lower branch of the left renal artery, and spontaneous renal rupture was diagnosed. Five months after the bleeding was stopped by selective transcatheter embolization of the branch of renal artery, CT showed an enhanced mass at the upper pole of left kidney and renal cell carcinoma (RCC) was suspected. Radical nephrectomy was performed, the pathological diagnosis was clear cell carcinoma, and the man has not experienced recurrence within 36 months after the surgery. RCC did not appear to be the cause of the original hemorrhage because there was a small residual hematoma in the middle of the renal parenchyma that was separated from the RCC. In cases of spontaneous renal rupture, re-evaluation by imaging studies is mandatory after disappearance of perirenal hematoma because imaging studies at the time of the rupture sometimes do not reveal the cause of the hemorrhage.

Objectives: To determine whether angiotensin II type 1 receptor (AT1R) expression and tumor angiogenesis in human bladder cancer (BCa) specimens acquired by transurethral resection (TUR). It has recently been reported that AT1R is expressed in several tumors and is involved in tumor angiogenesis. However, no study has investigated AT1R expression in association with angiogenesis in clinical specimens of bladder cancer. Methods: Surgical specimens were obtained from 108 patients who had undergone TUR for bladder cancer. All specimens were pathologically diagnosed as urothelial carcinoma. AT1R expression and microvessel density (MVD) were determined by immunostaining. The clinical and pathologic characteristics were retrospectively reviewed. Results: The MVD was greater in muscle-invasive BCa (MIBC; 29 cases, 34.4 ± 4.1/0.25 mm2) than in non-MIBC (NMIBC; 79 cases, 17.4 ± 1.1/0.25 mm2, P < .0001). AT1R expression was greater in the MIBC (P = .0004) and high-grade (P = .0063) specimens than in the NMIBC and low-grade specimens. In addition, the greater expression of AT1R was significantly associated with MVD (P < .05). In NMIBC, the factors significantly affecting recurrence-free survival on univariate analysis were AT1R (P = .02), MVD (P < .0001), tumor multiplicity (P = .0007), and bacille Calmette-Guérin intravesical instillation after TUR (P = .0026). Multivariate analysis revealed that tumor multiplicity and no BCG intravesical instillation after TUR were independent predictors of 5-year recurrence-free survival, and AT1R and MVD were independent predictors of 1-year recurrence-free survival (P < .01). Conclusions: AT1R expression and MVD were related to early intravesical recurrence in NMIBC. The results suggest that AT1R could become a new molecular target and a prognostic factor for NMIBC.

During cell division, one of the major features of somatic cell reprogramming by defined factors, cells are potentially exposed to DNA damage. Inactivation of the tumor suppressor gene p53 raised reprogramming efficiency but resulted in an increased number of abnormal chromosomes in established iPS cells. Ataxia-telangiectasia mutated (ATM), which is critical in the cellular response to DNA double-strand breaks, may also play an important role during reprogramming. To clarify the function of ATM in somatic cell reprogramming, we investigated reprogramming in ATM-deficient (ATM-KO) tail-tip fibroblasts (TTFs). Although reprogramming efficiency was greatly reduced in ATM-KO TTFs, ATM-KO iPS cells were successfully generated and showed the same proliferation activity as WT iPS cells. ATM-KO iPS cells had a gene expression profile similar to ES cells and WT iPS cells, and had the capacity to differentiate into all three germ layers. On the other hand, ATM-KO iPS cells accumulated abnormal genome structures upon continuous passages. Even with the abnormal karyotype, ATM-KO iPS cells retained pluripotent cell characteristics for at least 20 passages. These data indicate that ATM does participate in the reprogramming process, although its role is not essential.

A 59-year-old man had an elevated prostate-specific antigen (PSA) concentration (439 ng/mL) in December 2008. We diagnosed prostatic adenocarcinoma by prostate needle biopsy. CT and MRI showed a prostatic tumour with bone and lymph node metastases. Combined androgen blockade therapy reduced the PSA level temporarily. After the PSA level gradually started to increase again and reached 27.27 ng/mL in October 2010, the patient was diagnosed with castration-resistant prostate cancer and treated with docetaxel chemotherapy. Radiological examination detected left hydronephrosis and a tumour in the left lower ureter in March 2011. Retrograde pyelography and urine cytology of class 3 from the left ureter indicated that the ureteral mass was a urothelial carcinoma. A left nephroureterectomy was performed. After the operation, the pathological examination showed a metastatic prostate carcinoma, accompanied by a decrease in the serum PSA level from 59.56 to 45.33 ng/mL.

The first advance in the history of studies on prostate cancer (PCa) and androgens was the development of treatment with castration and administration of estrogen by Charles B. Huggins, who won the Nobel Prize in Physiology and Medicine. Since then, and for 70 years, androgen deprivation therapy has been the standard therapy for advanced PCa and the center of studies on PCa. However, recent advances have shed light on the relationship between androgens and the development or the progression of PCa. The use of 5AR inhibitors to prevent progression of PCa continues to be widely discussed. Discussion has been fueled by the findings of two large randomized, placebo-controlled trials: the Prostate Cancer Prevention Trial with finasteride and the Reduction by Dutasteride of Prostate Cancer Events trial. Does the development of PCa or progression to castration-resistant PCa depend on dihydrotestosterone (DHT)? Here, we summarize and discuss recent topics of local androgen production of DHT in PCa.

Renal cell carcinoma (RCC) represents over 80 % of kidney cancer, and about 30 % of the patients with RCC develop metastasis after the surgery. Invasion of basement membrane (BM) and extracellular matrix (ECM) is an essential event in tumor invasion and metastasis. Matrix metalloproteinases (MMPs), which digest the main components of BM and ECM, are expressed in RCC. Heparanase, which degrades heparan sulfate proteoglycans, is predominantly expressed in high-grade RCCs with a positive correlation with pathological tumor stage and poor prognosis. Bone metastasis is common among the patients with RCC, and increased osteoclastic activity was observed at metastatic sites. Receptor activator of nuclear factor κB ligand (RANKL), which plays an important role in osteoclastogenesis, is predominantly expressed in high-grade RCC and its expression level is associated with bone metastasis and prognosis. Epithelial-mesenchymal transition (EMT), a switch of epithelial cells to sarcomatoid phenotype, is considered to be critical step during metastasis, and Snail, a major regulator of EMT, is predominantly expressed in high-grade RCC, and high Snail expression is a worse prognostic factor. Accordingly, heparanase, RANKL and Snail may be targets for the development of anti-tumor therapies for RCCs.

Background. Few studies have described the clinical courses and outcomes in the bladder after treatment of intravesical recurrence after radical nephroureterectomy (RNU) in patients with primary upper tract urothelial carcinoma (UTUC). We investigated the indicators for predicting subsequent bladder outcomes after treatment of intravesical recurrence after RNU. Methods. A total of 241 patients with primary UTUC (pTa-4N0M0) who experienced intravesical recurrence after RNU were included. Of these patients, 101 (41.9 %) underwent Bacillus Calmette-Guérin treatments, whereas 49 (20.3 %) underwent intravesical chemotherapy. The median follow-up period after initial transurethral resection of the bladder tumor was 33 months. Relationships with bladder outcomes were analyzed by using multivariable analysis. Results. Ninety-six patients experienced intravesical recurrence, and bladder progression was observed in 13. Cumulative incidence rates of intravesical recurrence at 1 and 5 years after treatment of the first intravesical recurrence were 31.0 and 48.4 %, whereas those of bladder progression at 1 and 5 years thereafter were 2.4 and 8.0 %. Multivariate analysis showed that the number of recurrent tumors and pT1 tumors at the time of the first intravesical relapse were independent risk factors for subsequent intravesical recurrence. With respect to bladder progression, multivariate analysis showed that pT1 tumors, the appearance of concomitant carcinoma-in situ at the time of the first intravesical relapse, and the absence of the Bacillus Calmette-Guérin treatment were independent risk factors. Conclusions. This retrospective study presents a detailed picture of further bladder outcomes after intravesical recurrence after RNU in primary UTUC patients. The results may assist physicians to develop a more rational protocol in bladder surveillance.

This is the first case report describing a complete response to bicalutamide withdrawal that lasted for almost 2years in a patient with metastatic prostate cancer. An 80-year-old man who had prostate-specific antigen (PSA) level elevation (168.1ng/mL) visited our hospital in February 2010. Bone scintigraphy showed pelvic metastases. We started hormonal therapy with leuprorelin and bicalutamide. The PSA concentration decreased to <0.1ng/mL but started increasing again and reached 1.64ng/mL in October 2012, at which time bicalutamide administration was discontinued. The PSA concentration decreased again and has remained below the limit of sensitivity for almost 2years.

Prostate cancer (PCa) is the most common cancer type in men. One of the most troublesome aspects of PCa is that androgen-dependent PCa inevitably progresses to highly aggressive and life-threatening castration resistant prostate cancer (CRPC). Kinases are key regulators of critical cancer processes such as cancer cell proliferation, invasion, differentiation or angiogenesis. Recent advances have shed light on molecular targeting inhibitors of kinases in CRPC. Aberrant expression of certain kinases has been implicated in the development and progression of PCa. Among them, some kinase inhibitors have emerged as promising drug targets for CRPC. In this review, we provide an overview of new therapeutic agents which arrived in an advanced stage of clinical testing, especially focusing on the targets of HGF/c-Met and PI3K/AKT/mTOR signaling pathways.

An 80-year-old man with an elevated prostate-specific antigen (PSA) level of 120 ng/mL) presented to the hospital in February 2011. A prostate needle biopsy was performed, and pathological examination revealed prostatic adenocarcinoma. The Gleason score was 4+5=9. Computed tomography revealed metastases of the pelvic lymph nodes. Combined androgen blockade was started. The PSA concentration decreased to 1.68 ng/mL, but started increasing again in August 2012 to 6.08 ng/mL. Although bicalutamide was discontinued due to antiandrogen withdrawal syndrome, the PSA concentration increased even more. The PSA concentration reached 21.62 ng/mL in September 2012, at which time ethnylestradiol was started. The PSA concentration decreased again and has remained below the limit of sensitivity for almost 2 years. To our knowledge, this is first case report describing a complete response to ethnylestradiol that lasted for almost 2 years in a patient with castration-resistant prostate cancer.