Ismail Turker Koksal

Adenovirus-mediated IKKbetaKA expression sensitizes prostate carcinoma cells to TRAIL-induced apoptosis.

Despite the fact that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively induce apoptosis in cancer cells, TRAIL resistance in cancer cells has challenged the use of TRAIL as a therapeutic agent. First, prostate carcinoma cell lines (DU145, LNCaP and PC3) were screened for sensitivity to adenovirus delivery of TRAIL (Ad5hTRAIL). As amplified Ikappa B kinase (IKK) activity is responsible for the constitutive nuclear factor-κB (NF-κB) activation leading to uncontrolled cell growth and metastasis, a dual vector approach using both an adenovirus vector (Ad) expressing the dominant-negative mutant of IKKβ (AdIKKβKA) and Ad5hTRAIL was employed to determine if prostate cancer cells were sensitized to TRAIL in the setting of IKK inhibition. Inhibition of the NF-κB pathway through IKK blockade sensitized all three prostate cancer cell lines to TRAIL, regardless of NF-κB activation or decoy receptor gene expression. Moreover, a novel quantitative real-time RT-PCR assay and conventional flow cytometry analysis indicated that TRAIL-resistant DU145 and LNCaP cells, but not TRAIL-sensitive PC3 cells, expressed substantial amounts of TRAIL Decoy Receptor 4. In conclusion, TRAIL decoy receptor expression appeared to be the chief determinant of TRAIL resistance encountered in prostate carcinoma cell lines.

DcR2 (TRAIL-R4) siRNA and adenovirus delivery of TRAIL (Ad5hTRAIL) break down in vitro tumorigenic potential of prostate carcinoma cells.

High levels of decoy receptor 2 (DcR2; TRAIL-R4) expression are correlated with TRAIL resistance in prostate cancer cells. In addition, upregulation of TRAIL death receptor (DR4 and DR5) expression, either by ionizing radiation or chemotherapy, can sensitize cancer cells to TRAIL. Considering more than half of human cancers are TRAIL resistant, modulation of surface TRAIL receptor expression appears to be an attractive treatment modality to counteract TRAIL resistance. In this study, three siRNA duplexes targeting DcR2 receptor were tested. Ad5hTRAIL infections were performed to overexpress human full-length TRAIL to induce cell death, and the in vitro tumorigenic potential of prostate cancer cells was assessed using colony-forming assays on soft agar. The DU145 and LNCaP prostate cancer cell lines, which express high levels of DcR2, were resistant to Ad5hTRAIL-induced death. Downregulation of surface DcR2 expression by siRNA sensitized these prostate cancer cell lines to Ad5hTRAIL. In addition, DcR2 siRNA-mediated knockdown of DcR2, followed by Ad5hTRAIL infection, dramatically reduced the in vitro tumorigenic potential of prostate cancer cells. Collectively, our results suggest the potential for combining receptor-specific siRNA with TRAIL in the treatment of certain cancers.

Varicocele-Induced Testicular Dysfunction May Be Associated with Disruption of Blood-Testis Barrier

The objective of this study was to examine E-cadherin and α-catenin expression at the junctions between adjacent Sertoli cells in testicular specimens from patients with varicocele in order to determine the presence of a possible link between blood-testis barrier and pathophysiology of varicocele. A total of 51 testicular biopsies were obtained from 28 infertile men with unilateral or bilateral varicocele. Twenty-three patients had bilateral and 5 had unilateral varicocele, Grade I varicocele was detected in 30 (59%), grade II in 15 (29%) and grade III in 6 (12%) patients. Abnormal expression of E-cadherin and α-catenin at the junctions between adjacent Sertoli cells was demonstrated in 100% and 90% of the patients with varicocele, respectively. In those with grade I-III varicocele, the mean E-cadherin and α-catenin expression were 7.6 ± 11.4 and 39 ± 36; 7.6 ± 0.0 and 49 ± 30; 8.3 ± 9.3 and 58 ± 33, respectively, but the difference was not significant. Reduced E-cadherin and α-catenin expression at the junctions between adjacent Sertoli cells may be associated with disruption of blood-testis barrier in varicocele.

Tumor necrosis factor-related apoptosis inducing ligand-R4 decoy receptor expression is correlated with high Gleason scores, prostate-specific antigen recurrence, and decreased survival in patients with prostate carcinoma

OBJECTIVE Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) has recently been investigated because of its ability to selectively kill cancer cells. Despite recent publications mainly focusing on TRAIL resistance in cancer cells, little is known about how TRAIL contributes to the carcinogenesis process. Because the expression patterns of TRAIL and its receptors in patients with prostate carcinoma have recently been reported, this study investigated the significance of TRAIL and TRAIL receptor expression in connection to serum prostate-specific antigen (PSA) and Gleason scoring. MATERIALS AND METHODS A total of 98 patients were included in the study. Gleason scores, PSA, TRAIL, and TRAIL receptor expressions were used for the comparison purposes. The Spearman rho correlation test was administered to reveal the correlations among the variants. The Kruskal Wallis-Mann Whitney U or Friedman-Wilcoxon signed ranks test determined the statistical significance between the pairs. Multinomial and/or multiple binary logistic regression analyses were deployed to test whether TRAIL markers were independent variables to predict the prognosis of prostate cancer. Kaplan-Meier and log-rank tests were used to determine the survival rates. RESULTS High-serum PSA levels were correlated with higher levels of TRAIL and TRAIL receptor expressions. Patients with high Gleason scores had higher levels of TRAIL-R4 decoy receptor expression but lower levels of TRAIL death ligand expression. CONCLUSIONS TRAIL-R4 decoy receptor expression is strongly correlated with PSA recurrence, which is suggestive of poor prognosis. High levels of TRAIL-R4 expression but low levels of TRAIL death ligand expression are connected to decreased survival.

Reduced E-cadherin and α-catenin Expressions Have No Prognostic Role in Bladder Carcinoma

In various human cancers, dysfunction of the E-cad-herin-catenin complex is associated with a decrease in cellular and tissue differentiation, and with higher invasive and metastatic potentials. The objective of this study was to investigate E-cadherin and α-catenin expression in superficial noninvasive papillary TCC and invasive TCC, and correlate these results with pathological and clinical parameters. We have used immunohistochemistry to localize Ecadherin and α-catenin in 56 formalin-fixed, paraffin-embedded tissue blocks from 41 patients with superficial bladder cancer and 15 with invasive bladder cancer. The 46 male and 10 female patients had a mean age of 67 years, with range of 40 to 82 years. The mean follow-up time was 33.4 (range 5–120) months. Tumor grade 1:2:3 ratios were 5:32:19. In superficial bladder tumor, abnormal expression of E-cadherin and a-catenin was demonstrated in 37 and 71% of the tumors, respectively. In advanced bladder tumor, abnormal expression of E-cadherin and a-catenin was demonstrated in 80 and 100% of the tumors, respectively. Differences in expression of E-cadherin and α-catenin could be discerned between superficial and advanced bladder tumors (p=0.004, p=0.024, respectively). However, the association between E-cadherin and α-catenin expression and tumor grade was not statistically significant (p>0.05). In addition, the expression of E-cadherin and α-catenin did not correlate with tumor number and size (p>0.05). We have demonstrated that abnormal expression of E-cadherin and/or α-catenin occurs in more than 85% of bladder carcinomas and correlates significantly only with advanced stage. Nevertheless, these observations need to be confirmed in larger prospective clinical studies.

Differential PTEN Protein Expression Profiles in Superficial versus Invasive Bladder Cancers

Introduction: The prognostic significance of PTEN protein loss in bladder cancer is not well established. The objective of this study was to investigate the PTEN expression profile in superficial noninvasive papillary transitional cell carcinoma (TCC) versus invasive TCC and compared the results with pathological and clinical parameters. Materials and Methods: Bladder tumor samples were obtained from 29 patients who underwent surgery for superficial (n = 11) and invasive (n = 18) bladder cancers at the Akdeniz University Hospital. The patient profile including sex, age, histological grade and the stage, presence of carcinoma in situ, cystoscopy findings (tumor size, location, multiplicity) were obtained by examining the patients’ medical records. No patient received anticancer agents prior to the operation. Western blotting was performed using bladder carcinoma samples in order to determine the level of PTEN protein expression for each patient. Results: Only 4 (13.7%) patients with bladder carcinoma manifested a decrease in the level of PTEN expression. Regarding the correlation between tumor stage and the PTEN expression, with the exception of patient 23 all patients who displayed a reduction in PTEN expression had muscle-invasive TCC. Conclusion: Future studies with a clinical follow-up will be needed to determine if those superficial tumors with decreased PTEN expression are going to progress to a later stage. Based on our results PTEN by itself does not seem to be a good candidate as an independent marker to predict the behavior of bladder cancers.

The potential role of inducible nitric oxide synthase (iNOS) activity in the testicular dysfunction associated with varicocele: an experimental study.

Nitric oxide (NO) has been reported to be increased in the spermatic veins of men affected by varicocele. The aim of the present study was to determine whether iNOS (inducible nitric oxide synthase) has a role in testicular dysfunction associated with varicocele, immunohistochemistry analyze was used to study iNOS activity in testis of adolescent rats with experimental left varicoceles. Rats were randomly divided into three groups. The first group consisted of rats undergoing partial ligation of left renal vein (n:12). The second group consisted of rats undergoing a sham operation (n:6) and, the third group referred to as control rats (n:7). Immunohistochemistry slides were evaluated by counting the number of positive cells and expressed as percents (% iNOS activity). We found that iNOS was predominantly expressed in the cytoplasm of Leydig cells in each group and only a small amount of iNOS was expressed in Sertoli cells. There were significant differences in % iNOS activity between both testes of varicocele group and both of testes control group(p < 0.01), but no significant differences were noted between other groups (p > 0.05). Because of iNOS activity was markedly increased in the Leydig cells of varicocele bearing rats, we suggest that iNOS activity may play a role in the testicular dysfunction associated with varicocele during adolescence.

Lymph nodal involvement by renal angiomyolipoma

Angiomyolipoma of the kidney is a clonal neoplasm, apparently part of a family of neoplasms derived from perivascular epithelial cells. A 40‐year‐old woman presented with right flank pain and an otherwise non‐significant medical history. An abdominal computed tomography scan revealed an 18 cm solid mass in the mid‐portion of the right kidney and multiple perihilar lymph nodes. Presumptive diagnosis was renal cell carcinoma. Right radical nephrectomy and a perihilar lymph node dissection was performed through a Chevron incision for the anticipated diagnosis of renal adenocarcinoma. The renal tumor was diagnosed as angiomyolipoma and a component was identified pathologically in a dissected lymph node. There was no evidence of tumor recurrence in the follow‐up period of eight years. The consensus from other studies suggests that this phenomenon is a manifestation of the multicentric nature of angiomyolipoma, rather than due to metastasis. Genetic studies may resolve this question in the future.

Role of TNF-related apoptosis-inducing ligand (TRAIL) in the pathogenesis of varicocele-induced testicular dysfunction.

The higher frequency of varicocele in men with infertility has drawn attention and resulted in increased research at the molecular level towards treatments. The aim of this study was to investigate the role of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its receptors in varicocele-induced testicular dysfunction in an experimental rat model. The rats were divided into three groups: control, sham and varicocele. Varicoceles in rats were induced by partial ligation of the left renal vein and left testes. The rats were analyzed 13 weeks after surgery. The degree of DNA fragmentation within cells in the testis was determined using terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL) assay. Tubule degeneration was evaluated using the Johnsen score. The expression of TRAIL and its receptors was detected by immunohistochemical and Western blotting techniques. The apoptotic index, Johnsen score and the expression of TRAIL and TRAIL receptors were examined. The data are presented as the mean±s.d. and were analyzed using computer software. The Kruskal-Wallis and Dunns multiple comparison tests were used in the statistical analyses. The germ cell apoptotic index was increased in rats with varicoceles when compared with the sham and control groups (P=0.0031). The Johnsen score was significantly decreased in the varicocele group when compared with the sham and control groups (P<0.0001). Immunohistochemical and Western blotting analyses showed that after varicocele induction, the expression of TRAIL-R1 and TRAIL-R4 in germ cells was increased and the expression of TRAIL-R2 was decreased. There are no significant differences among the groups in terms of TRAIL and TRAIL-R3 receptor expression. The results of this study indicate that TRAIL and its receptors may have a potential role in the pathogenesis of varicocele-induced testicular dysfunction.

Impact of chronic renal failure and peritoneal dialysis fluids on advanced glycation end product and iNOS levels in penile tissue: an experimental study

OBJECTIVES To investigate the impact of chronic renal failure (CRF) on advanced glycation end product and inducible nitric oxide synthase (iNOS) in penile tissue, we examined the advanced glycation end product 5-hydroxy methyl furfural (5-HMF) content and iNOS expression in rats in which uremia had been produced by greater than 85% nephrectomy. In addition, the contribution of peritoneal dialysis (PD) fluids to the elevation of penile tissue 5-HMF levels and iNOS staining scores has been investigated. METHODS Adult male Wistar rats, aged between 10 and 12 weeks and weighing 200 to 330 g, were divided into five groups that each included 6 animals. The first group served as a control group. In the second group, CRF was induced and a peritoneal catheter was implanted, but PD was not performed. In group 3, CRF was induced and PD was performed using dialysis fluids containing 1.36% glucose and icodextrin. In group 4, CRF was also induced and PD was performed using 3.86% glucose and icodextrin. Finally, in group 5, without CRF, an indwelling catheter was implanted, and the PD procedure was performed using dialysis fluids containing 3.86% glucose and icodextrin. RESULTS The elevation in 5-HMF levels and iNOS staining scores in penile tissue from groups 2, 3, 4, and 5 was significant compared with group 1 (P <0.05). The elevation in 5-HMF levels and iNOS staining scores was also significant between groups 2 and 3, 2 and 4, 3 and 4, 3 and 5, and 4 and 5 (P <0.05). Moreover, the correlation between the 5-HMF levels and iNOS staining scores was statistically significant (r = 0.525, P = 0.003). CONCLUSIONS In the present experimental study, we found that 5-HMF levels and iNOS staining scores were significantly elevated in rat penile tissue in which uremia had been produced compared with the groups without CRF. Additionally, PD fluids containing glucose had an effect on the elevation of penile tissue 5-HMF levels and iNOS staining scores.