[Pedunculated Giant Condyloma Acuminatum of the Scrotum].

The patient was a 71-year-old male whose chief complaint was a scrotum mass. The mass had gradually increased in size without any associated symptoms. The physical examination revealed a pedunculated, radish brown, and elastic soft tumor (4. 5×3. 5×3. 0 cm) in the right scrotum. Blood chemical analysis of HbA1c and squamous carcinoma antigen were 8. 3% and 38. 4 ng/ml (≦1. 5), respectively. This tumor was successfully treated with surgical resection. Histopathological examination showed condyloma acuminatum without malignant findings. Giant condyloma acuminatum commonly affects the genital and perianal areas. An immunocompromised state generally exists in the background of the patients.

[Occurrence of Distant Metastasis During Bladder Presevation in T1 high-grade Bladder Cancer: Report of Three Cases].

We report three patients with T1 high-grade (HG) bladder cancer who suffered from distant metastasis during bladder preservation. The patients were a 48-year-old female (Case 1), a 75-year-old female (Case 2) and an 82-year-old male (Case 3) with the chief complaint of asymptomatic gross hematuria. The histopathological diagnoses of the initial transurethral resection of the bladder tumor (TURBT) and second TURBT were urothelial carcinoma, pT1, HG and no malignancy in all three patients. Bladder tumors of all patients revealed sessile growth pattern and no presence of carcinoma in situ. Case 2 and 3 did not receive BCG vesical instillation after the second TURBT. Lymph node metastases appeared in Case 1 and Case 2 and lung metastasis appeared in Case 3. Tumor budding (TB) was positive in Case 1 and Case 2. Variant histology (VH) of nested morphology was detected in Case 1 and VH of inverted morphology in Case 2 and Case 3. Twenty-four months after the initial TURBT, Case 1 died due to cancer progression after cisplatin-based chemotherapy and pembrolizumab therapy. Thirty-three and 11 months after the initial TURBT, Case 2 and Case 3 were alive without cancer progression after cisplatin-based chemotherapy and/or pembrolizumab therapy, respectively. The two patients with T1 HG bladder cancer with TB had lymphatic metastasis and the patient without TB had hematogenous metastasis. Nested morphology is reportedly categorized as high-risk disease and inverted morphology as low-risk disease. TB might be correlated with lymphatic metastasis in T1 HG bladder cancer, and TB should be considered in the management of T1 HG bladder cancer. In the case of VH, the guidelines should be followed during the treatment decision of T1 HG bladder cancer.

Clinical, pathological, and therapeutic features of newly diagnosed prostate cancer predominantly detected by opportunistic PSA screening: A survey of Shiga Prefecture, Japan.

BACKGROUND: In all the prefectures of Japan, with the exception of Shiga Prefecture, more than half of local governments have an organized prostate-specific antigen (PSA) screening system in place. However, in the Shiga Prefecture, only a single city performed PSA screening over the time period of this survey. The purpose of the present study was to determine the clinical, pathological, and therapeutic features of newly diagnosed prostate cancer in localities where a formally organized screening system was almost entirely absent. METHODS: A multicenter observational study was conducted in the Shiga Prefecture, which has the lowest rate of population-based PSA-screening in Japan. Patients' age, initial PSA, reasons for PSA testing, Gleason score, clinical stage, and primary treatments were surveyed. We stratified patients according to the reasons for PSA measurement, and compared the differences between groups subject to organized versus opportunistic screening. RESULTS: In the 2 years 2012 and 2017, 984 newly diagnosed prostate cancer patients were analyzed. Of these, 954 (97%) were opportunistically tested (i.e., not as part of an organized screening system), with the remaining 29 (3%) measured as part of an organized screening program. Patients in the former group exhibited a higher initial PSA value than in the organized screening group (median: 11.49 vs. 5.67 ng/ml). They also had worse clinical features, including higher Gleason score and TNM stage. More patients in the organized screening group were treated curatively than in the nonorganized screening group in terms of the primary treatment. The results were similar in a subanalysis of the patients of age 50-69 years. CONCLUSIONS: Organized PSA screening contributes to increasing the number of patients diagnosed with early-stage cancer who can be treated curatively.

Antitumor activity of potent pyruvate dehydrogenase kinase 4 inhibitors from plants in pancreatic cancer.

Phosphorylation of pyruvate dehydrogenase by pyruvate dehydrogenase kinase 4 (PDK4) 4 inhibits its ability to induce a glycolytic shift. PDK4 expression is frequently upregulated in various cancer tissues, with its elevation being critical for the induction of the Warburg effect. PDK4 is an attractive target for cancer therapy given its effect on shifting glucose metabolism. Previous research has highlighted the necessity of identifying a potent compound to suppress PDK4 activity at the submicromolar concentrations. Here we identified natural diterpene quinones (KIS compounds) that inhibit PDK4 at low micromolar concentrations. KIS37 (cryptotanshinone) inhibited anchorage-independent growth in three-dimensional spheroid and soft agar colony formation assays of KRAS-activated human pancreatic (MIAPaCa-2 and Panc-1) and colorectal (DLD-1 and HCT116) cancer cell lines. KIS37 also suppressed KRAS protein expression in such cell lines. Furthermore, KIS37 suppressed phosphorylation of Rb protein and cyclin D1 protein expression via the PI3K-Akt-mTOR signaling pathway under nonadherent culture conditions and suppressed the expression of cancer stem cell markers CD44, EpCAM, and ALDH1A1 in MIAPaCa-2 cells. KIS37 also suppressed pancreatic cancer cell growth in both subcutaneous xenograft and orthotopic pancreatic tumor models in nude mice at 40 mg/kg (intraperitoneal dose) without any evident toxicity. Reduced ALDH1A1 expression was observed in KIS37-treated pancreatic tumors, suggesting that cancer cell stemness was also suppressed in the orthotopic tumor model. The aforementioned results indicate that KIS37 administration is a novel therapeutic strategy for targeting PDK4 in KRAS-activated intractable human pancreatic cancer.

Intravesical bacillus Calmette-Guerin therapy after second transurethral resection for primary T1 bladder cancer.

BACKGROUND: To evaluate the effect of intravesical bacillus Calmette-Guerin (BCG) instillation therapy after second transurethral resection (TUR) on primary T1 bladder cancer. METHODS: The subjects were 180 patients diagnosed with T1 bladder cancer at our university and at affiliated hospitals between January 1990 and December 2015. Tumor residual rate, intravesical recurrence rate, and risk factors for intravesical recurrence were investigated. RESULTS: The median follow-up period was 26 (1-175) months. Of the 180 patients, 78 (43%) underwent a second TUR. Residual tumors were detected in 42 patients (53.8%), and no up-staging cases were observed. Within the whole group, 42 patients were treated with intravesical BCG therapy following a second TUR (group 1), 36 were treated with second TUR alone (group 2), 28 were treated with intravesical BCG therapy alone (group 3), and 74 were treated without second TUR or intravesical BCG therapy (group 4). The 1- and 5-year recurrence-free survival rates of the four groups were 80.7 and 59.7% (group 1), 69.0 and 26.3% (group 2), 76.3 and 56.6% (group 3), 64.6 and 48.6% (group 4), respectively. There was no significant difference between group 1 and group 3 (p = 0.401). Intravesical BCG therapy was the only factor preventing intravesical recurrence (p = 0.013). CONCLUSIONS: Intravesical BCG therapy alone showed a significant preventive effect with regard to intravesical recurrence. In our cohort, however, second TUR did not improve recurrence-free survival in those individuals who underwent BCG instillation.

The drs tumor suppressor regulates glucose metabolism via lactate dehydrogenase-B.

Previously, we showed that drs contributes to suppression of malignant tumor formation in drs-knockout (KO) mice. In this study, we demonstrate the regulation of glucose metabolism by drs using comparisons of drs-KO and wild-type (WT) mouse embryonic fibroblasts (MEFs). Extracellular acidification, lactate concentration, and glucose consumption in drs-KO cells were significantly greater than those in WT cells. Metabolomic analyses also confirmed enhanced glycolysis in drs-KO cells. Among glycolysis-regulating proteins, expression of lactate dehydrogenase (LDH)-B was upregulated at the post-transcriptional level in drs-KO cells and increased LDH-B expression, LDH activity, and acidification of culture medium in drs-KO cells were suppressed by retroviral rescue of drs, indicating that LDH-B plays a critical role for glycolysis regulation mediated by drs. In WT cells transformed by activated K-ras, expression of endogenous drs mRNA was markedly suppressed and LDH-B expression was increased. In human cancer cell lines with low drs expression, LDH-B expression was increased. Database analyses also showed the correlation between downregulation of drs and upregulation of LDH-B in human colorectal cancer and lung adenocarcinoma tissues. Furthermore, an LDH inhibitor suppressed anchorage-independent growth of human cancer cells and MEF cells transformed by activated K-ras. These results indicate that drs regulates glucose metabolism via LDH-B. Downregulating drs may contribute to the Warburg effect, which is closely associated with malignant progression of cancer cells.

[Modified Toyoda Method for Complete Duplex Ureters in Tubeless Cutaneous Ureterostomy : Report of a Case].

A 65-year-old man underwent radical cystectomy and cutaneous ureterostomy for bladder cancer. Because the patient had left complete duplex ureters,we modified the Toyoda method to construct the tubeless cutaneous ureterostomy with a unilateral stomal creation. The adhesive portion of both ureteral walls in duplex ureters was simultaneously cut approximately 5 mm from the distal end longitudinally,and the common sheath of the cut portion of the ureters was cut approximately 5 mm longitudinally in order to separate the two ureters. This procedure was repeated to make a"fish-mouth"aperture. Two opened ureteral walls were formed into the upper and lower plates of the Toyoda method stoma,respectively. To our knowledge,this is the first report of a surgical procedure of the tubeless cutaneous ureterostomy in complete duplex ureters.

[Clinical Study of Percutaneous Radiofrequency Ablation for Small Renal Tumor].

Percutaneous radiofrequency ablation (PRFA) has been applied as an option of minimally invasive treatment for small renal tumor. We retrospectively evaluated 5 patients with small renal tumor for whom PRFA was performed at our hospital. The average age was 69.6 years (range 45-86), average tumor diameter 20.0 mm (8-34), average preoperative glomerular filtration rate (eGFR) 66.8 ml/min/1.73m2 (42. 1-93.2), and follow-up period was 23.4 months (8-34). There were two minor complications (grade 1), including perirenal hematoma and pain at the probe insertion site in each patient. One patient had local recurrence 22 months after PRFA and the additional PRFA will be performed. PRFA could be a feasible, safe and effective therapy for small renal tumor.

Female-specific rectal carcinogenesis in cyclin D1b transgenic mice.

Human cyclin D1 generates two major isoforms via alternative splicing: cyclin D1a and cyclin D1b. Cyclin D1b is hardly expressed in normal tissues but is frequently expressed in certain types of cancer tissues. To clarify the oncogenic potential of cyclin D1b variant, we developed cyclin D1b transgenic (Tg) mice and analyzed their phenotypes. We detected rectal tumors in 63% (15/24) of the female Tg mice. All rectal tumors had the histological characteristics similar to human sessile serrated adenoma/polyps (SSA/Ps). Adenocarcinomas were also found in 53% (8/15) of the rectal tumors, suggesting that these adenocarcinomas originated from the SSA/P-like lesions. No rectal tumors were found in the ovariectomized female cyclin D1b Tg mice (0/10), indicating that ovarian hormones played a critical role in rectal carcinogenesis in these Tg mice. Both phosphorylation of Erk, without activating MEK, and expression of estrogen receptor ß were elevated in the rectal tumors of female cyclin D1b Tg mice compared with normal rectums of female wild-type mice. In addition, we established a cell line, D1bTgRT, derived from a rectal cancer of female Tg mouse. Small interfering RNA-induced cyclin D1b knockdown in this cell line suppressed Erk phosphorylation, anchorage-independent growth, cell invasiveness and tumorigenicity in nude mice. In humans, expression of cyclin D1b messenger RNA was detected in 17% (1/6) of colorectal cancer cell lines and 9.7% (3/31) of colorectal cancer tissues. Taken together, these results indicate that cyclin D1b expression contributes to the female- specific rectal carcinogenesis in mouse model.

Population­based prostate­specific antigen screening for prostate cancer may have an indirect effect on early detection through opportunistic testing in Kusatsu City, Shiga, Japan.

Prostate cancer is the most common genitourinary cancer in men. Population-based serum prostate-specific antigen (PSA) testing is used to screen men for the early detection of asymptomatic prostate cancer. The present study compared the features of patients with prostate cancer in Kusatsu City, the only municipality in Shiga Prefecture of Japan to implement organized PSA screening, with those in other municipalities. The target population for organized PSA screening by mail invitation was men ≥50 years. Patients were pathologically diagnosed via prostate biopsy because of elevated serum PSA. This multicenter observational study was subsequently conducted in 14 hospitals. The following information was extracted from patient records: age, reason for PSA testing, initial PSA level, Gleason score, clinical stage, and place of residence. Risk classification was defined as low, intermediate, high, and advanced. Each patient was stratified according to their city/town. A total of 984 patients diagnosed with prostate cancer in Shiga in 2012 and 2017 were analyzed, of which 955 (97%) were opportunistically tested, with the remaining 29 (3%) assessed by organized screening. In Kusatsu, 93 patients were diagnosed, of whom 26 (28%) were detected by organized screening. By contrast, only three of 891 patients (0.3%) were detected by organized screening in other municipalities. Of patients in Kusatsu, cases identified by opportunistic testing had a higher initial PSA value (P=0.010) than those identified by organized screening. However, patients detected through opportunistic testing in Kusatsu City were younger (P=0.034), had a lower PSA value (P=0.001), and improved risk classification (P<0.001) than those in other municipalities. It was concluded that more patients were diagnosed with early-stage cancer by organized PSA screening. Furthermore, population-based PSA screening in Kusatsu City may have indirectly affected early detection, even by opportunistic testing.

[Psoas abscess after ureteral stent exchange for cutaneous ureterostomy: report of a case].

A 69-year-old man underwent a radical cystectomy and cutaneous ureterostomy for carcinoma in situ of the urinary bladder. The ureteral stents were exchanged for cutaneous ureterostomy 35 days after the operation. The patient suffered from high fever with chills a few hours after the stent exchange, and was readmitted to our hospital. High fever was not improved by treatment with Ceftriaxone for 5 days. Five days after the stent exchange, computed tomography (CT) revealed a right psoas abscess. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in the blood culture. Urine culture showed MRSA, Pseudomonas aeruginosa and Enterococcus faecium. Computed tomography-guided percutaneous catheter drainage and treatment consisting of vancomycin, minocycline and ciprofloxacin were performed for the psoas abscess. This treatment significantly reduced the size of the abscess and high fever was improved. The catheter was removed 22 days after the drainage. However, magnetic resonance imaging revealed a spondylitis at L4 and L5. Therefore, antibiotics treatment was continued for about 3 months. There has been no sign of recurrence of bladder cancer and psoas abscess at 23 months after the operation.

Application of the indocyanine green fluorescence imaging method in laparoscopic resection of a solitary retroperitoneal metastasis of renal cell carcinoma: A case report.

Fluorescence image-guided surgery has improved intraoperative identification of anatomic structures including visualization of vascular anatomy. Herein, indocyanine green (ICG) fluorescence imaging was applied to identify of a recurrent small tumor of renal cell carcinoma (RCC) during laparoscopic surgery. The patient underwent left laparoscopic radical nephrectomy via the retroperitoneal approach for RCC (clear cell carcinoma, pT1bN0M0) at the age of 39 years. A solitary retroperitoneal mass (14 mm in diameter) was identified in a computed tomography scan 6 years after surgery. We performed laparoscopic resection with the application of the ICG angiography, because RCC is recognized as one of the most hypervascular cancers. The tumor was clearly visualized by fluorescence. Histopathological diagnosis of the resected tumor was recurrent RCC (low grade, G1). The patient remained free of disease at 2 years after surgery. The ICG fluorescence imaging would be a useful method for identification of metastatic small lesions of RCC during laparoscopic surgery.

Cryptotanshinone suppresses tumorigenesis by inhibiting lipogenesis and promoting reactive oxygen species production in KRAS­activated pancreatic cancer cells.

Pyruvate dehydrogenase kinase 4 (PDK4) is an important regulator of energy metabolism. Previously, knockdown of PDK4 by specific small interfering RNAs (siRNAs) have been shown to suppress the expression of Κirsten rat sarcoma viral oncogene homolog (KRAS) and the growth of lung and colorectal cancer cells, indicating that PDK4 is an attractive target of cancer therapy by altering energy metabolism. The authors previously reported that a novel small molecule, cryptotanshinone (CPT), which inhibits PDK4 activity, suppresses the in vitro three­dimensional (3D)­spheroid formation and in vivo tumorigenesis of KRAS­activated human pancreatic and colorectal cancer cells. The present study investigated the molecular mechanism of CPT­induced tumor suppression via alteration of glutamine and lipid metabolism in human pancreatic and colon cancer cell lines with mutant and wild­type KRAS. The antitumor effect of CPT was more pronounced in the cancer cells containing mutant KRAS compared with those containing wild­type KRAS. CPT treatment decreased glutamine and lipid metabolism, affected redox regulation and increased reactive oxygen species (ROS) production in the pancreatic cancer cell line MIAPaCa­2 containing mutant KRAS. Suppression of activated KRAS by specific siRNAs decreased 3D­spheroid formation, the expression of acetyl­CoA carboxylase 1 and fatty acid synthase (FASN) and lipid synthesis. The suppression also reduced glutathione­SH/glutathione disulfide and increased the production of ROS. Knockdown of FASN suppressed lipid synthesis in MIAPaCa­2 cells, partially promoted ROS production and mildly suppressed 3D­spheroid formation. These results indicated that CPT reduced tumorigenesis by inhibiting lipid metabolism and promoting ROS production in a mutant KRAS­dependent manner. This PDK4 inhibitor could serve as a novel therapeutic drug for KRAS­driven intractable cancers via alteration of cell metabolism.

[Incidence and risk factors of early postoperative paralytic ileus after radical cystectomy and cutaneous ureterostomy with a unilateral and parallel stoma].

To identify the incidence and risk factors for developing early postoperative paralytic ileus (POPI) after radical cystectomy and cutaneous ureterostomy with a unilateral and parallel stoma, we retrospectively reviewed 21 patients (mean age 73.0, 19 males and 2 females) with a minimum of 3 months of follow-up. POPI occurred in 4 patients (19.0%), who did not need surgical treatment and the insertion of a nasogastric tube. Age and past history of abdominal surgery influenced the occurrence of POPI. The patients with and without POPI had a mean age of 82.3±7.4 and 70.8±6.3 years old, respectively (p＝0.0025), and 75.0% (3/4) and 11.8% (2/17) of the patients, respectively, had a past history of abdominal surgery (p＝ 0.0276). There were no significant differences between patients with and without POPI in any of the following factors examined : sex, body mass index, American Society of Anesthesiologists score, pT-category, neoadjuvant chemotherapy, preoperative serum levels of hemoglobin, creatinine, total protein, and albumin, operative time, blood loss, transfusion volume, stomal side, postoperative day of ambulation, and removal of epidural anesthesia tube. In conclusion, our results showed that increasing age and a past history of abdominal surgery were significantly associated with the occurrence of POPI after radical cystectomy and cutaneous ureterostomy.

Cryptotanshinone, a novel PDK 4 inhibitor, suppresses bladder cancer cell invasiveness via the mTOR/ß­catenin/N­cadherin axis.

The phosphorylation of pyruvate dehydrogenase (PDH) by pyruvate dehydrogenase kinase (PDK) 4 inhibits its ability to induce a glycolytic shift. PDK4 expression is upregulated in various types of human cancer. Because PDK4 regulation is critical for metabolic changes in cancer cells, it is an attractive target for cancer therapy given its ability to shift glucose metabolism. It was previously shown that a novel PDK4 inhibitor, cryptotanshinone (CPT), suppressed the three­dimensional (3D)­spheroid formation of pancreatic and colorectal cancer cells. In the present study, the effects of CPT on the invasiveness of bladder cancer cells were investigated. CPT significantly suppressed the invasiveness and 3D­spheroid formation of T24 and J82 bladder cancer cells. CPT also suppressed the phosphorylation of PDH and ß­catenin, as well as the expression of N­cadherin, which are all critical for inducing epithelial­mesenchymal transition (EMT). The knockdown of ß­catenin or PDK4 using specific small interfering RNAs suppressed N­cadherin expression and invasiveness in T24 cells. An mTOR inhibitor also suppressed the phosphorylation of ß­catenin and N­cadherin expression. Furthermore, CPT injection significantly suppressed pancreatic tumor growth and peritoneal dissemination of highly metastatic SUIT­2 pancreatic cancer cells in a mouse orthotopic pancreatic cancer model, without evident toxicity. Moreover, immunohistochemistry analyses demonstrated decreased ß­catenin expression in CPT­treated pancreatic tumors compared with control tumors. Taken together, these results indicate that CPT reduced the invasiveness and metastasis of bladder cancer cells by suppressing EMT via the mTOR/ß­catenin/N­cadherin pathway.

Single Short Retention Instillation of Pirarubicin Prevents Intravesical Recurrence of Low-risk Non Muscle Invasive Bladder Cancer.

BACKGROUND: This study evaluated the efficacy of a single instillation of pirarubicin with a short retention time for preventing intravesical recurrence of low-risk non-muscle-invasive bladder cancer. PATIENTS AND METHODS: We analyzed 165 patients with low-risk non-muscle-invasive bladder cancer who underwent transurethral surgery. Single instillation of pirarubicin with 15-min retention time immediate after surgery was performed in 47 (28%) patients. The other patients (118, 72%) were treated without instillation therapy. The primary endpoint was recurrence-free survival. RESULTS: Median overall follow-up was 50 (range=6-134) months. Recurrence-free survival at 1 and 5 years was 91% and 72%, and 79% and 54% in the group treated with pirarubicin, and that treated with surgery alone, respectively (p=0.031). Cox's hazard analysis revealed lack of instillation and larger tumor size (>10 mm) as significant factors for risk of recurrence. No adverse events regarding intravesical chemotherapy were observed. CONCLUSION: Pirarubicin instillation with 15-min retention time can prevent intravesical recurrence of low-risk bladder tumors.

[false-positive results of human chorionic gonadotropin ß measurement after high orchiectomy for stage i seminoma: report of a case].

A 21-year-old male presented at our hospital with a complaint of left scrotal swelling. The serum human chorionic gonadotropin-ß (hCG-ß) level was 1.3 ng/ml. A left high orchitectomy was performed, and a histological study demonstrated seminoma. Computerized tomography showed no evidence of metastasis. Adjuvant radiation therapy with 25 Gy was performed for stage I seminoma. Although complete clinical remission was achieved,the hCG-ß level remained slightly positive (0.3-0.5 ng/ml). The urine hCG-ß-core fragment was determined to be within normal limits. This confirmed that the result of serum hCG-ß measurement was false-positive in our case. The patient received no additional treatment, and is free from recurrence 3 years and 1 month after surgery. In the testicular germ cell tumors,the measurement of urine hCG-ß-core fragment is useful for differential diagnosis in cases of low level-positive serum hCG-ß without clinical evidence of disease.

Cyclin D1b variant promotes cell invasiveness independent of binding to CDK4 in human bladder cancer cells.

Alternative splicing in the cyclin D1 gene produces cyclin D1b variant which lacks a C-terminal region containing the threonine-286 (T286) phosphorylation site required for nuclear export. We have shown that the expression of the cyclin D1b variant is detected in about 60% of human bladder cancer tissues (15/26) and cell lines (3/5). To examine the role of the cyclin D1b variant in bladder carcinogenesis, we introduced wild-type cyclin D1a, cyclin D1b variant or mutant cyclin D1-T286A cDNAs into a human bladder cancer cell line, SBT991, in which cyclin D1b transcript was not expressed, and compared their oncogenic activities. Ectopic expression of cyclin D1b promoted cell invasiveness and anchorage-independent growth of the cancer cells. On the other hand, cyclin D1-T286A enhanced anchorage-independent growth, but did not promote cell invasiveness. The amount of nuclear-localized cyclin D1b and cyclin D1-T286A was higher than that of nuclear-localized cyclin D1a. In addition, introduction of siRNA specific for cyclin D1b into cells of the T24 bladder cancer cell line, in which cyclin D1b transcript was expressed, significantly suppressed cell invasiveness. Immunoprecipitation analysis revealed that cyclin D1a and cyclin D1-T286A could bind to cyclin-dependent kinase 4 (CDK4) but cyclin D1b has lost its capacity to associate with CDK4. Unlike cyclin D1a and cyclin D1-T286A, expression of cyclin D1b did not enhance phosphorylation of Rb protein in SBT991 cells. These results indicate that cyclin D1b promotes cell invasiveness independent of binding to CDK4 to enhance Rb phosphorylation.

Suppression of cell invasiveness by periostin via TAB1/TAK1.

We have previously shown that the expression of periostin is significantly downregulated in human bladder cancer tissues and that periostin suppresses cell invasiveness and metastasis of cancer cells. To clarify the molecular mechanism of this suppression by periostin, we searched for periostin-binding proteins and identified TAB1, which interacts with and activates TAK1, by mass analysis of proteins co-precipitated with periostin in 293T cells expressing periostin. The association between periostin and TAB1 was confirmed by a pulldown assay in 293T cells co-tranfected with expression plasmids of periostin, TAB1 and TAK1. TAK1 was also co-precipitated with periostin in this assay. Co-transfection experiments in 293T also showed that periostin could activate TAK1. Introduction of siRNA for TAB1 suppressed TAK1 activation by periostin. Analyses with deletion mutants of periostin revealed that the C-terminal region of periostin was necessary and sufficient for the association with TAB1 and the TAK1 activation. The suppression of invasiveness by periostin was attenuated by siRNA targeting TAK1 or TAB1 in 293T (human embryonic kidney) and T24 (human bladder carcinoma) cell lines. These findings indicate that periostin is involved in the suppression of cell invasiveness via the TAB1/TAK1 signaling pathway.

Downregulation of drs tumor suppressor gene in highly malignant human pulmonary neuroendocrine tumors.

Neuroendocrine tumors in the lung fall into four categories: typical carcinoid tumor (TC), atypical carcinoid tumor (AC), large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung carcinoma (SCLC), in ascending order of malignancy. The drs gene was originally isolated as a suppressor against v-src transformation and was shown to induce apoptosis in human cancer cells. The expression of drs was markedly downregulated in various human cancer tissues and cell lines. Furthermore, drs knockout mice showed a tumor-prone phenotype, indicating that drs acts as a tumor suppressor gene in malignant tumor formation. To clarify the role of the drs gene in the development of human pulmonary neuroendocrine tumors, we examined the expression of drs mRNA in tissue specimens from 3 cases of TC, 4 cases of AC, 2 cases of LCNEC, and 11 cases of SCLC by in situ mRNA hybridization. Four cases of normal lung and bronchial epithelia, 8 samples of normal brain tissue, and 2 cases of tumorlets in the lung were also examined. The drs mRNA was definitely expressed in all normal tissues of the lung and brain, and 3 TC and 2 tumorlet tissues. The expression of drs mRNA was also detected in 2 of 2 LCNEC tissues and 3 of 4 AC tissues, although the signals were weak. On the other hand, drs mRNA was not detected in 10 of 11 SCLC tissues. Downregulation of drs mRNA was also observed in 3 of 4 SCLC cell lines that were examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Neither gross deletion nor rearrangement of the drs genome was detected in these cell lines by Southern blot analysis. Our results indicate that the downregulation of drs is correlated with the development of SCLC, a highly malignant pulmonary neuroendocrine tumor.