No abstract

Proteome analysis of bladder cancer with narrow-range pH 2-DE has identified a novel protein on chromosome 7 encoded by ORF 24 (C7orf24) as one of the highly expressed proteins in cancer cells. C7orf24 is currently registered in the protein database as a hypothetical protein with unknown function. The homologs of C7orf24 in other animals have also been registered as putative protein genes. Western blot analysis using a mAb against C7orf24 confirmed its higher expression in bladder cancer compared with normal tissue. Several other cancer cell lines were also found to express C7orf24. However, the introduction of C7orf24 into Rat-1 or NIH3T3 cells did not cause malignant transformation. A stable transfectant of NIH3T3 cells with recombinant retrovirus vector was produced for a growth rate assay, and a higher growth rate was observed in C7orf24-expressing cells compared with the controls. Six kinds of small interfering RNAs (siRNAs) were then produced, and C7orf24-siRNA#5 showed a strong knockdown effect on protein expression and significant antiproliferative effects on cancer cell lines were demonstrated by the MTT assay. Therefore, C7orf24 may have an important role in cancer cell proliferation, and may be an appropriate therapeutic target molecule against cancer.

Purpose: New markers that enable the percentage of transitional cell carcinomas (TCC) of the bladder that are diagnosed before invasion of the bladder muscle layers to be increased would reduce the morbidity and mortality associated with this disease. The purpose of this study was to develop a simple, accurate urine test based on mRNA markers and simple gene signatures that (a) could detect TCC before muscle invasion while maintaining high specificity in patients with hematuria or urinary tract infections and (b) identify patients most likely to have grade 3 or stage zT1disease. Experimental Design: RNA markers with high overexpression in stage Ta tumors and/or T1 to T4 tumors but low expression in blood or inflammatory cells were characterized by quantitative reverse transcription-PCR using 2 mL of voided urine from 75 TCC patients and 77 control patients with other urological diseases. Results: A combination of the RNAs CDC2, MDK, IGFBP5, and HOXA13 detected 48%, 90%, and 100% of stage Ta, T1, and >T1 TCCs, respectively, at a specificity of 85%. Detection of Ta tumors increased to 60% for primary (non-recurrent) Ta tumors and 76% forTa tumors z1cm in diameter. Test specificity was 80% for the 20 control patients with urinary tract infections. The combination of CDC2 and HOXA13 distinguished between grade 1 to 2 TCCs and grade 3 or stage zT1TCCs with f80% specificity and sensitivity. Conclusions: Simple gene expression signatures can be used as urine markers for the accurate detection and characterization of bladder cancer.There are f360,000 new cases of bladder cancer worldwide annually and f145,000 deaths from the disease (1). About 30% of tumors have invaded into or beyond the muscularis propria at the time of diagnosis. Patients with these muscleinvasive tumors (stages T2-T4) have 10-year recurrence-free survival rates ranging from >80% for organ-confined tumors to f30% for tumors with regional lymph node metastases (2). Muscle-invasive tumors are generally treated by radical cystectomy with bilateral pelvic lymph node dissection followed by urinary diversion. In contrast, tumors that have not invaded the muscularis propria (stage Ta, T1, and in situ carcinomas) are usually resected by organ-preserving transurethral resection and present 10-year survival rates of 70% to 85% (2). Screening high-risk groups, such as the elderly, cigarette smokers, and certain occupational groups including truck drivers, painters, and workers in the textile dye and rubber tire industries (3, 4), would be predicted to lead to a higher proportion of tumors being identified at the pre -muscle-invasive stage and an overall decrease in the bladder cancer burden.Recent studies using high-throughput microarray analysis have shown that mRNA expression profiles are a powerful method for discriminating between bladder tumors and normal urothelium and defining subgroups of bladder tumors (5-8). The informativeness of these expression profiles and the high frequency of tumor cell exfoliation into urine have raised the prospect of...

We and others previously showed that signaling through cSrc or atypical protein kinase C (aPKC) pathway regulates the proliferation of prostate cancer cells and is associated with their progression to castrate-resistance in vivo. However, the interrelation of these two kinases has been largely unexplored. In the present study, we show that androgen-induced activation of cSrc regulates the activity of aPKC through the small molecular weight G protein Rac1 in androgen-dependent LNCaP cells. Knockdown of cSrc in those cells reduces the phosphorylation of aPKC and the abundance of activated form of Rac1. Additionally, the treatment of those cells with Rac1 inhibitor repressed cell cycle progression at G(1)/S transition. In fact, forced expression of a constitutively active Rac1 mutant in LNCaP cells promoted cell proliferation under androgen-depleted conditions both in vitro and in vivo. Moreover, LNCaP C4-2 and AILNCaP cells, the syngeneic androgen-independent sublines from LNCaP cells, harbored abundant Rac1-GTP. Importantly, the inhibition of Rac1 suppressed cell proliferation and induced apoptotic cell death in all prostate cancer cell lines tested irrespective of their androgen-dependence. In immunohistochemical evaluation of tumor specimens from prostate cancer patients, Rac1 pathway appeared to be activated in the majority of castrate-resistant diseases. Collectively, our present results both in vitro and in vivo highly implicate that Rac1 can be a potential therapeutic target for patients with advanced prostate cancer, especially those with castrate-resistant status.

Recent studies suggest that SIPA1 encoding a Rap GTPase-activating protein SPA-1 is a candidate metastasis efficiency-modifying gene in human breast cancer. In this study, we investigated the expression and function of SPA-1 in human prostate cancer (CaP). Immunohistochemical studies of tumor specimens from CaP patients revealed a positive correlation of SPA-1 expression with disease progression and metastasis. The correlation was recapitulated in human CaP cell lines; LNCaP that rarely showed metastasis in SCID mice expressed an undetectable level of SPA-1, whereas highly metastatic PC3 showed abundant SPA-1 expression. Moreover, SIPA1 transduction in LNCaP caused prominent abdominal lymph node metastasis without affecting primary tumor size, whereas shRNA-mediated SIPA1 knockdown or expression of a dominant-active Rap1 mutant (Rap1V12) in PC3 suppressed metastasis. LNCaP transduced with SPA-1 (LNCaP/SPA-1) showed attenuated adhesion to the precoated extracellular matrices (ECM) including collagens and fibronectin, due to defective ECM-medicated Rap1 activation. In addition, LNCaP/SPA-1 showed a diminished level of nuclear Brd4, which is known to bind SPA-1, resulting in reduced expression of a series of ECM-related genes. These results suggest that SPA-1 plays an important role in controlling metastasis efficiency of human CaP by regulating the expression of and interaction with ECM in the primary sites. (Cancer Sci 2011; 102: 828-836) P rostate cancer (CaP) is the most common male malignancy in the Western world.(1) Data from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute between 1999 and 2006 indicated that 16% of patients presented regional lymph node involvement or distant metastasis at the time of diagnosis. Importantly, those with distant metastasis showed poor prognosis with a 5-year survival rate of 30.2% (http://www.seer.cancer.gov/). Thus, clarification of molecular mechanisms of metastasis (2) is a crucial step towards establishing a new therapeutic strategy.Cancer metastasis consists of a series of complex processes, and multiple genetic factors may be involved in the metastatic efficiency, such as mutations accumulated during primary tumor evolution, genetic features intrinsic to the original tumor cell clones and host genetic backgrounds. (3,4) One of the initial steps of metastasis is invasion and detachment of tumor cells from the primary tissues, in which the interaction of tumor cells with ECM plays an important role. (5,6) In agreement, among numerous metastasis-predictive genes in various tumors, the common molecular signature of metastasis involves those related to ECM interactions. (7)(8)(9) Accumulating evidence indicates an important role of Rap signaling in controlling cell-ECM and cell-cell adhesion, in part via regulation of integrins and cadherins.(10,11) Rap signaling is controlled by multiple regulatory factors, including Rap GDP ⁄ GTP exchange factors and Rap GTPase-activating proteins (GAP), (12) and the deregulation may profoundly af...