Objectives. To determine the association between obesity and prostate cancer recurrence after primary treatment with radical prostatectomy. Methods. Data were abstracted from CaPSURE, a disease registry of 10,018 men with prostate cancer. We included 2131 men who had undergone radical prostatectomy between 1989 and 2003 and had body mass index (BMI) information available. Recurrence was defined as two consecutive prostate-specific antigen (PSA) levels of 0.2 ng/mL or greater or any second treatment. Patients were risk stratified using the PSA level, Gleason grade, and clinical T stage. Results. Patients were followed up for a median of 23 months. Of the 2131 patients, 251 (12%) developed recurrence at a median of 13 months (range 1 to 107); 183 (9%) of these men had PSA failure and 68 (3%) received a second treatment. After adjusting for risk group, ethnicity, age, and comorbidities, a significant association was found between an increasing BMI and disease recurrence (P ϭ 0.028). Very obese patients (BMI 35 kg/m 2 or more) were 1.69 times more likely to have recurrence relative to men of normal weight (BMI less than 25.0 kg/m 2 ; 95% confidence interval [CI] 1.01 to 2.84). An increasing PSA level (P Ͻ0.0001) and Gleason grade (P Ͻ0.0001) were also associated with recurrence. Ethnicity was not significantly associated with either BMI or PSA recurrence (P ϭ 0.685 and P ϭ 0.068, respectively). Conclusions. The results of our study have shown that obesity is an independent predictor of prostate cancer recurrence. Because of the increased comorbidities and greater rates of recurrence, obese individuals undergoing radical prostatectomy need vigilant follow-up care. UROLOGY 66: 1060-1065, 2005.

A novel protein kinase whose activity can be stimulated by mitogen in vivo was cloned and characterized. The cDNA of this gene encodes an 802-amino acid protein (termed RLPK) with the highest homology (37% identity) to the two protein kinase families, p90 RSK and p70 RSK . Like p90 RSR , but not p70 RSK , RLPK also contains two complete nonidentical protein kinase domains. RLPK mRNA is widely expressed in all human tissues examined and is enriched in the brain, heart, and placenta. In HeLa cells, transiently expressed epitopetagged RLPK can be strongly induced by epidermal growth factor, serum, and phorbol 12-myristate 13-acetate, but only moderately up-regulated by tumor necrosis factor-␣ and other stress-related stimuli. The activity of RLPK stimulated by epidermal growth factor was not inhibited by several known protein kinase C inhibitors nor by rapamycin, a known specific inhibitor for p70 RSK , but could be inhibited by herbimycin A, a tyrosine kinase inhibitor, and partially inhibited by PD98059 or SB203580, inhibitors for the mitogen-activated protein kinase pathways. Recombinant RLPK possesses high phosphorylation activity toward histone 2B and the S6 peptide, RRRLSSLRA. Although purified recombinant RLPK can be phosphorylated by ERK2 and p38␣ in vitro, its activity is not affected by this phosphorylation. Moreover, the treatment of RLPK with acid phosphatase did not reduce its in vitro kinase activity. These data suggest that RLPK is structurally similar to previously isolated RSKs, but its regulatory mechanism may be distinct from either p70 RSK or p90 RSK s. RSK respond to growth factor-related stimuli, quite different mechanisms have been implicated in the regulation of these kinases. The p70 RSK is rapamycin-sensitive and relies on multisite phosphorylation to be activated (31-33). The interactions with Rho family members such as RAC1 and Cdc2 may be crucial for p70 RSK activation (34). As for p90 RSK s, ERK1 and ERK2 were believed to be responsible, at least in part, for their activation (4,35,36). Despite the progress in this field, regulation mechanisms and biological functions of these two RSK protein kinase families are still largely unknown.In this study, we reported cloning and characterization of RLPK, a novel protein kinase with two kinase domains. The overall sequence identity of this kinase to p90 RSK s is about 37%, which is much lower than that within the p90 RSK family (79 -82%), suggesting that while it is homologous to p90 RSK s, it is not an isoform of p90 RSK family. Despite the distinct amino acid sequence of RLPK, we have found similarities in its substrate specificity and activation profile to that of both p90 RSK and p70 RSK . We demonstrated that the intrinsic activity of recombinant RLPK is not dependent on phosphorylation and cannot be regulated by MAP kinases in vitro. Therefore, RLPK may represent another class of kinase with two kinase domains, and its regulation mechanism and function may differ from that of p90 RSK and p70 RSK . EXPERIMENTAL PROCEDURESMaterials-Pfu DNA...

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Multidrug resistance 1 (MDR1) gene encodes for P-glycoprotein (P-gp), a Mr 170,000 transmembrane calcium-dependent efflux pump that is inactivated in prostate cancer. We hypothesize that inactivation of the MDR1 gene through CpG methylation contributes to the pathogenesis and progression of prostate cancer. To test this hypothesis, CpG methylation status of the MDR1 promoter and its correlation with clinicopathological findings were evaluated in 177 prostate cancer samples and 69 benign prostate hypertrophy (BPH) samples. Cellular proliferation index and apoptotic index were determined by proliferating cell nuclear antigen (PCNA) and single-strand DNA immunostaining, respectively. After 5-aza-2-deoxycytidine treatment, increased expression of MDR1 mRNA transcript was found in prostate cancer cell lines (DU145, DuPro, and ND1). MDR1 methylation frequency was significantly higher in prostate cancer samples compared with BPH samples (54.8 versus 11.6%, respectively, P < 0.001). Logistic regression analysis revealed that PC patients are 11.5 times more likely to have MDR1 methylation than BPH patients (95% confidence interval 4.87-27.0) and that MDR1 methylation is independent of the age. Significant correlation of MDR1 methylation was observed with high pT category (P < 0.001), high Gleason sum (P ‫؍‬ 0.008), high preoperative prostate-specific antigen (P ‫؍‬ 0.01), and advancing pathological features. In addition, PCNA-labeling index were significantly higher in methylation-specific PCR (MSP)-positive than in MSP-negative prostate cancer samples (P ‫؍‬ 0.048). In contrast, no significant difference in apoptotic index was found between MSP-positive and -negative prostate cancer samples. These findings suggest that CpG hypermethylation of MDR1 promoter is a frequent event in prostate cancer and is related to disease progression via increased cell proliferation in prostate cancer cells.