John Papadopoulos

Circulating monocytes expressing CD31: Implications for acute and chronic angiogenesis

To identify the roles of various circulating cells (eg, endothelial and/or stem and progenitor cells) in angiogenesis, we parabiosed a wild-type syngeneic mouse with a transgenic syngeneic green fluorescent protein mouse. Following the establishment of a common circulation between these parabionts, we investigated acute (7 to 10 days), subacute (2 to 3 weeks), and chronic (4 to 6 weeks) phases of angiogenesis in wild-type mice using wound healing, implanted gel foam fragments, and subcutaneous tumor assays, respectively. We found that under in vitro conditions, circulating murine monocytes expressed F4/80, CD31, and vascular endothelial growth factor receptor 2, but neither CD133 nor von Willebrand factor, whereas murine endothelial cells expressed CD31, vascular endothelial growth factor receptor 2, and von Willebrand factor, but neither CD133 nor F4/80. Immunofluorescence analysis revealed that green fluorescent protein-positive cells in the walls of new vessels in wounds, gel foam blocks, and tumors expressed both F4/80 and CD31, that is, macrophages. Pericytes, cells that express both CD31 and desmin, were found both in the walls of tumor-associated vessels and within tumors. Collectively, these data demonstrate that monocytes (ie, cells that express both CD31 and F4/80) may be recruited to the site of tissue injury and directly contribute to angiogenesis, reaffirming the close relationships between various cell types within the reticuloendothelial system and suggesting possible targets for anticancer treatments.

Neoadjuvant Platelet Derived Growth Factor Receptor Inhibitor Therapy Combined With Docetaxel and Androgen Ablation for High Risk Localized Prostate Cancer

PURPOSE Platelet derived growth factor receptor inhibitor therapy improves the efficacy of taxane chemotherapy in preclinical models of prostate cancer. Men with high risk localized prostate cancer were treated with platelet derived growth factor receptor inhibitor therapy, docetaxel and hormone ablation in the preoperative setting, and clinicopathological outcomes were evaluated. MATERIALS AND METHODS A total of 36 men with cT2 or greater disease, Gleason grade 8-10, serum prostate specific antigen more than 20 ng/ml or cT2b and prostate specific antigen more than 10 ng/ml and Gleason 7 disease, without radiological evidence of metastases, were scheduled to receive intramuscular leuprolide, 600 mg daily oral imatinib and 30 mg/m(2) weekly docetaxel x 4 every 42 days for 3 cycles before radical prostatectomy (beta [0.02, 1.98] prior on the possibility of pathological complete remission). Unresectable disease, postoperative prostate specific antigen 0.2 ng/ml or greater, or administration of postoperative radiation or hormones were defined as treatment failure. RESULTS A total of 39 men were registered over 15 months. Median patient age was 57 years (range 44 to 71). Risk factors included T3 disease (22 of 39), Gleason 8-10 disease (31 of 39) and prostate specific antigen more than 20 ng/ml (12 of 39). Three men were ineligible or declined therapy, 29 of 36 (81%) received 3 cycles of therapy and 7 of 36 (19%) discontinued therapy related to toxicity. Grades 3-4 toxicity included rash (4), diarrhea (4), fatigue (6) and neutropenia (1). The surgical approach was feasible, without excessive or unusual complications such as wound dehiscence. No pathological complete remissions were defined. At a median followup of 39 months 53% were free from progression. CONCLUSIONS Evidence for a favorable impact of platelet derived growth factor receptor inhibitor therapy on the efficacy of neoadjuvant docetaxel and hormonal ablation in high risk localized prostate cancer was not obtained.

Consistent interactions between tumor cell IL-6 and macrophage TNF-α enhance the growth of human prostate cancer cells in the bone of nude mouse

To test the hypothesis that tumor-associated macrophages (TAMs) enhance the growth and metastasis of human prostate cancer in the bone, we evaluated the effects of decreasing interleukin-6 (IL-6) production by tumor cells and TAMs in a mouse model of bone metastasis. Human PC-3MM2 cells that produce IL-6 were transfected with lentivirus containing IL-6 small hairpin RNA (shRNA) or nonspecific RNA and injected into the tibias of nude mice treated intraperitoneally every 5days for 5weeks with phosphate-buffered saline (PBS), liposomes containing PBS, or liposomes containing clodronate (to decrease the number of macrophages). Transfection of PC-3MM2 cells with IL-6 shRNA significantly decreased cellular expression of IL-6 and the number of TAMs and osteoclasts in bone tumors, which correlated with significant decreases in tumor size, bone lysis, and incidence of lymph node metastasis. Treatment of mice with clodronate liposomes significantly decreased the number of TAMs and osteoclasts in the bone tumors, the expression of IL-6 in the PC3-MM2 cells, and the production of tumor necrosis factor (TNF)-α by TAMs. These findings correlated with a significant decrease in tumor size, bone lysis, and lymph node metastasis. Knocking down IL-6 in tumor cells and decreasing TAMs was associated with the lowest incidences of bone tumors and lymph node metastasis. These results suggest that TAMs enhance the growth of prostate cancer cells in the bone.

Disease reclassification risk with stringent criteria and frequent monitoring in men with favourable‐risk prostate cancer undergoing active surveillance

To determine the frequency of disease reclassification and to identify clinicopathological variables associated with it in patients with favourable‐risk prostate cancer undergoing active surveillance (AS).

Induction and Maintenance Adjuvant Mitomycin C Topical Therapy for Upper Tract Urothelial Carcinoma: Tolerability and Intermediate Term Outcomes

PURPOSE Endoscopic management of upper tract urothelial carcinoma (UTUC) is associated with higher recurrences, which could be reduced by application of topical therapy. Adjuvant induction Bacillus Calmette-Guerin has shown inferior outcomes for UTUC compared to bladder cancer, and maintenance regimens for UTUC are unexplored. We report on the efficacy, safety, and tolerability of Mitomycin C (MMC) induction and maintenance adjuvant topical therapy for UTUC. MATERIALS AND METHODS Patients with UTUC who received adjuvant topical therapy after complete endoscopic control of Ta/T1 tumors were retrospectively reviewed. Patients were treated using percutaneous nephrostomy tube (NT) or cystoscopically placed weekly ureteral catheters, per patient preference, and all patients were offered induction and maintenance. Standardized follow-up of every 3 months in the first year, then at a minimum every 6 months, with ureteroscopy and at least annual CT, was performed. Primary outcomes were recurrence-free, progression-free, nephroureterectomy-free rate and cancer-specific and overall survival. Secondary outcomes were safety and treatment tolerability. RESULTS Twenty-seven patients with 28 renal units received adjuvant topical therapy from January 2008 to March 2015. Median follow-up was 19 months (range 7-92). Three year recurrence-free, progression-free, and nephroureterectomy-free survival rates were 60% [confidence interval (95% CI): 42, 86%], 80% [95% CI: 64, 100%], and 76% [95% CI: 60, 97%]. Cancer-specific mortality rate was 0%, and 3-year overall survival was 92.9%. Nine patients experienced adverse outcomes, all related to interventions and none related to systemic toxicity. CONCLUSIONS Induction and maintenance adjuvant topical MMC for endoscopically resected UTUC is feasible, well tolerated and shows promising intermediate term data on recurrence, progression, and nephroureterectomy-free survival.

THE MITOTOIC SPINDLE APPARATUS INHIBITOR AZD4877 HOLDS PROMISE AS A NOVEL THERAPEUTIC OPTION AGAINST HUMAN BLADDER CANCER

INTRODUCTION AND OBJECTIVE: The treatment of advanced blader cancer with combination of sorafenib and classical chemotherapeutics is currently under investigation in clinical trials. Sorafenib (BAY 43-9006) is a bi-aryl urea which inhibits a variety of RTKs like VEGFR-2/3, PDGFR, Flt-3, and c-Kit but also directly targets the Raf/Mek/Erk pathway by inhibiting the Raf isoforms Raf-1 (C-Raf) and B-Raf. Therefore, we studied the effects of sorafenib on intracellular singaling pathways, migration, proliferation, and apoptosis in different urothelial cancer cells. METHODS: The human bladder cancer cell lines RT4, T24 and J82 were used for the experiments. Migration was studied in a twodimensional wounded layer assay. Cell proliferation was quantified after 24 and 48 hours of treatment by cell counts. Cell signaling pathways (Erk1/2, Akt, p38) were studied by Western blotting.. Apoptosis was studied by the measurement of Annexin-V binding (flow cytometry) and PARP cleavage (Western blotting). Western blots were quantified by calibrated densitometry. RESULTS: As expected, a concentration-dependent inhibition of basal Erk1/2 phosphorylation, cell migration and proliferation was observed at pharmacological concentrations (> 3 μM) of sorafenib. In addition, sorafenib (10 μM) was found to significantly (p<0.05, n=4-5) induce apoptosis of T24 and J82 but not of RT4 cells. Surprisingly, at low concentrations (0.1 μM), the compound significantly (p<0.05, n=9) stimulated posphorylation of Erk-1/2 in all cell lines studied. In contrast, no stimulatory effects on Akt or p38 phosphorylation were detected. Further series of experiments were undertaken to study possible functional consequences of these findings. Interestingly, a significant (p<0.05, n=6) stimulation of migration of RT4 and T24 cells by sorafenib (0.1 μM) was observed. In addition, sorafenib (0.1 μM) significantly (p<0.05, n=56) stimulated the proliferation of T24 and J82 cells. The MEK inhibitor U0126 (10 μM) completely prevented the stimulatory effects of sorafenib on ERK-1/2 phosphorylation and migration, indicating a functional effect located upstream of the MEK/ERK system. CONCLUSIONS: In this work, we clearly demonstrated a stimulatory effects on different bladder cancer cells of sorafenib at low concentrations (0.1 μM). This finding has important clinical consequences with regard to the dosing regimes (avoidance of low trough plasma concentrations) of this important anti-tumor compound.