Wolfgang Schultze-Seemann

Vaccination of advanced prostate cancer patients with PSCA and PSA peptide-loaded dendritic cells induces DTH responses that correlate with superior overall survival

Prostate stem cell antigen (PSCA) and prostate‐specific antigen (PSA) are overexpressed in most prostate cancers. PSCA‐ and PSA‐derived, HLA‐A2 binding peptides are specific targets for T‐cell responses in vitro. A phase I/II trial was performed to demonstrate feasibility, safety and induction of antigen‐specific immunity by vaccination with dendritic cells (DC) presenting PSCA and PSA peptides in patients with hormone‐ and chemotherapy‐refractory prostate cancer. Patients received 4 vaccinations with a median of 2.7 × 107 peptide‐loaded mature DC s.c. in biweekly intervals. Clinical responses were assessed 2 weeks after the 4th vaccination. Immune monitoring was performed by DTH and HLA multimer analysis. Twelve patients completed vaccination without relevant toxicities. Six patients had stable disease after 4 vaccinations. One patient had a complete disappearance of lymphadenopathy despite rising PSA. Four patients with SD and 1 progressor developed a positive DTH after the 4th vaccination. With a median survival of all patients of 13.4 months, DTH‐positivity was associated with significantly superior survival (p = 0.003). HLA tetramer analysis detected high frequencies of peptide‐specific T cells after 2 vaccinations in 1 patient who was also the sole responder to concomitant hepatitis B vaccination as an indicator of immune competence and survived 27 months after start of vaccination. Vaccination with PSA/PSCA peptide‐loaded, autologous DCs may induce cellular responses primarily in immunocompetent patients, which appear to be associated with clinical benefit. Testing of DC‐based vaccination is warranted for patients at earlier stages of prostate cancer.

Salvage Lymph Node Dissection with Adjuvant Radiotherapy for Nodal Recurrence of Prostate Cancer

PURPOSE We evaluated the impact of salvage lymph node dissection with adjuvant radiotherapy in patients with nodal recurrence of prostate cancer. By default, nodal recurrence of prostate cancer is treated with palliative antihormonal therapy, which causes serious side effects and invariably leads to the development of hormone refractory disease. MATERIALS AND METHODS A total of 47 patients with nodal recurrence of prostate cancer based on evidence of (11)C-choline/(18)F-choline ((18)F-fluorethylcholine) positron emission tomography-computerized tomography underwent primary (2 of 52), secondary (45 of 52), tertiary (4 of 52) and quaternary (1 of 52) salvage lymph node dissection with histological confirmation. Of 52 salvage lymph node dissections 27 were followed by radiotherapy. Biochemical response was defined as a prostate specific antigen less than 0.2 ng/ml after salvage therapy. The Kaplan-Meier method, binary logistic regression and Cox regression were used to analyze survival as well as predictors of biochemical response and clinical progression. RESULTS Mean prostate specific antigen at salvage lymph node dissection was 11.1 ng/ml. A mean of 23.3 lymph nodes were removed per salvage lymph node dissection. Median followup was 35.5 months. Of 52 salvage lymph node dissections 24 resulted in complete biochemical response followed by 1-year biochemical recurrence-free survival of 71.8%. Gleason 6 or less (OR 7.58, p = 0.026), Gleason 7a/b (OR 5.91, p = 0.042) and N0 status at primary therapy (OR 8.01, p = 0.011) were identified as independent predictors of biochemical response. Gleason 8-10 (HR 3.5, p = 0.039) as a preoperative variable, retroperitoneal positive lymph nodes (HR 3.76, p = 0.021) and incomplete biochemical response (HR 4.0, p = 0.031) were identified as postoperative predictors of clinical progression. Clinical progression-free survival was 25.6% and cancer specific survival was 77.7% at 5 years. CONCLUSIONS Based on (11)C/(18)F-choline positron emission tomography-computerized tomography as a diagnostic tool, salvage lymph node dissection is feasible for the treatment of nodal recurrence of prostate cancer. Most patients experience biochemical recurrence after salvage lymph node dissection. However, a specific population has a lasting complete prostate specific antigen response.

A bispecific diabody directed against prostate-specific membrane antigen and CD3 induces T-cell mediated lysis of prostate cancer cells

BackgroundAlthough cancer of the prostate is one of the most commonly diagnosed cancers in men, no curative treatment currently exists after its progression beyond resectable boundaries. Therefore, new agents for targeted treatment strategies are needed. Cross-linking of tumor antigens with T-cell associated antigens by bispecific monoclonal antibodies have been shown to increase antigen-specific cytotoxicity in T-cells. Since the prostate-specific membrane antigen (PSMA) represents an excellent tumor target, immunotherapy with bispecific diabodies could be a promising novel treatment option for prostate cancer.MethodsA heterodimeric diabody specific for human PSMA and the T-cell antigen CD3 was constructed from the DNA of anti-CD3 and anti-PSMA single chain Fv fragments (scFv). It was expressed in E. coli using a vector containing a bicistronic operon for co-secretion of the hybrid scFv VHCD3-VLPSMA and VHPSMA-VLCD3. The resulting PSMAxCD3 diabody was purified from the periplasmic extract by immobilized metal affinity chromatography (IMAC). The binding properties were tested on PSMA-expressing prostate cancer cells and PSMA-negative cell lines as well as on Jurkat cells by flow cytometry. For in vitro functional analysis, a cell viability test (WST) was used. For in vivo evaluation the diabody was applied together with human peripheral blood lymphocytes (PBL) in a C4-2 xenograft-SCID mouse model.ResultsBy Blue Native gel electrophoresis, it could be shown that the PSMAxCD3 diabody is mainly a tetramer. Specific binding both to CD3-expressing Jurkat cells and PSMA-expressing C4-2 cells was shown by flow cytometry. In vitro, the diabody proved to be a potent agent for retargeting PBL to lyze C4-2 prostate cancer cells. Treatment of SCID mice inoculated with C4-2 tumor xenografts with the diabody and PBL efficiently inhibited tumor growth.ConclusionsThe PSMAxCD3 diabody bears the potential for facilitating immunotherapy of prostate cancer and for the elimination of minimal residual disease.

Positron Emission Tomography (PET) Imaging of Prostate Cancer with a Gastrin Releasing Peptide Receptor Antagonist - from Mice to Men

Ex vivo studies have shown that the gastrin releasing peptide receptor (GRPr) is overexpressed on almost all primary prostate cancers, making it a promising target for prostate cancer imaging and targeted radiotherapy. Methods: Biodistribution, dosimetry and tumor uptake of the GRPr antagonist 64Cu-CB-TE2A-AR06 [(64Cu-4,11-bis(carboxymethyl)-1,4,8,11-tetraazabicyclo(6.6.2)hexadecane)-PEG4-D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-LeuNH2] were studied by PET/CT in four patients with newly diagnosed prostate cancer (T1c-T2b, Gleason 6-7). Results: No adverse events were observed after injection of 64Cu-CB-TE2A-AR06. Three of four tumors were visualized with high contrast [tumor-to-prostate ratio > 4 at 4 hours (h) post injection (p.i.)], one small tumor (T1c, < 5% tumor on biopsy specimens) showed moderate contrast (tumor-to-prostate ratio at 4 h: 1.9). Radioactivity was cleared by the kidneys and only the pancreas demonstrated significant accumulation of radioactivity, which rapidly decreased over time. Conclusion: 64Cu-CB-TE2A-AR06 shows very favorable characteristics for imaging prostate cancer. Future studies evaluating 64Cu-CB-TE2A-AR06 PET/CT for prostate cancer detection, staging, active surveillance, and radiation treatment planning are necessary.

Three conformational antibodies specific for different PSMA epitopes are promising diagnostic and therapeutic tools for prostate cancer.

The prostate specific membrane antigen (PSMA) represents an attractive antigen for antibody‐based diagnostic and therapeutic intervention in prostate cancer, since it is highly restricted to the prostate and overexpressed in all tumor stages. The present work describes the in vitro characterization of the three anti‐PSMA monoclonal antibodies (mAbs) 3/A12, 3/E7, and 3/F11 in comparison to the mAb J591.

Bilateral pedicled myocutaneous vertical rectus abdominus muscle flaps to close vesicovaginal and pouch-vaginal fistulas with simultaneous vaginal and perineal reconstruction in irradiated pelvic wounds.

Chronic postoperative pouch-vaginal and vesicovaginal fistulas after hysterectomy and irradiation to treat advanced cervical cancer do not respond to conventional treatment because of the low vascularity in the irradiated area. We present the successful repair of these complications in a female patient, in whom several vaginal and abdominal approaches had been tried and had resulted not only in failure but also in tissue loss and fibrosis and persisting fistulas. First, a synchronous vaginoabdominal approach using a vertical myocutaneous distally based rectus abdominis myocutaneous flap was used successfully to close a pouch-vaginal fistula and simultaneously reconstruct the posterior vaginal wall. In a second approach, the persisting vesicovaginal fistula was closed by a right rectus abdominis myocutaneous flap while simultaneously reconstructing the anterior vaginal wall, closing the enterocutaneous stoma and performing an appendicovesicostomy as a continence channel for catheterization. Despite unfavorable local wound situations, including an enterocutaneous stoma through the rectus abdominis and various previous incision lines, the transfer of axially well-vascularized tissue can solve these problem wounds. Consecutive bilateral use of the rectus abdominis flap may be necessary to deal with extensive pelvic wounds. This technique should be considered as one repair modality in irradiated pelvic wounds with fistulas. Previous enterostomy is not a contraindication to the use of this flap.

Th1 and Th2 Cytokine Response Patterns in Leukocyte Cultures of Patients with Urinary Bladder, Renal Cell and Prostate Carcinomas

As a decreased production of Th1 cytokines by stimulated peripheral blood leukocytes has recently been shown in patients with various carcinomas, the present study was performed to determine whether these patients also exhibit a Th1/Th2 imbalance compared to healthy controls. We measured the production of the Th1 cytokines IL-2 and IFN-γ as well as the Th2 cytokines IL-4, IL-6 and IL-10 in mitogen-stimulated peripheral blood mononuclear cell (PBMC) cultures of patients with urinary bladder carcinomas (n = 47), prostate carcinomas (n = 111) and renal cell carcinomas (n = 67) as compared to 40 age-matched healthy controls. In the PBMC cultures of the tumor patients, the levels of the Th1 cytokines IL-2 and IFN-γ were lower as compared to the controls. For IFN-γ, the differences were highly significant and in the patients with renal cell carcinomas it could be shown that the values decreased with increasing tumor mass. In contrast, the levels of the Th2 cytokines IL-4, IL-6 and IL-10 were comparable in the PBMC cultures of tumor patients and controls. From these results, it is concluded that there is only a malfunction in Th1 cells but no switch from a Th1 type to a Th2 type cytokine profile in the PBMCs of cancer patients.

Detection of local recurrent prostate cancer after radical prostatectomy in terms of salvage radiotherapy using dynamic contrast enhanced-MRI without endorectal coil.

PurposeTo evaluate the value of dynamic contrast enhanced Magnetic Resonance Imaging (DCE-MRI) without endorectal coil (EC) in the detection of local recurrent prostate cancer (PC) after radical prostatectomy (RP).Material and methodsThirty-three patients with recurrent PC underwent DCE-MRI without EC before salvage radiotherapy (RT). At median 15 (mean 16±4.9, range 12–27) months after completion of RT all patients showed complete biochemical response. Additional follow up post RT DCE-MRI scans were available. Prostate specific antigen (PSA) levels at the time of imaging were correlated to the imaging findings.ResultsIn 22/33 patients (67%) early contrast enhancing nodules were detected in the post-prostatectomy fossa on pre-RT DCE-MRI images. The average pre-RT PSA level of the 22 patients with positive pre-RT DCE-MRI findings was significantly higher (mean, 0.74±0.64 ng/mL) compared to the pre-RT PSA level of the 11 patients with negative pre-RT DCE-MRI (mean, 0.24±0.13 ng/mL) (p<0.001). All post-RT DCE-MRI images showed complete resolution of initial suspicious lesions. A pre-RT PSA cut-off value of ≥0.54 ng/ml readily predicted a positive DCE-MRI finding.ConclusionsThis is the first study that shows that DCE-MRI without EC can detect local recurrent PC with an estimated accuracy of 83% at low PSA levels. All false negative DCE-MRI scans were detected using a PSA cut-off of ≥0.54 ng/mL.

Immunotherapy with dendritic cells for prostate cancer

Radical prostatectomy for prostate cancer is followed by PSA recurrence in up to 40% of patients. One third of patients with biochemical relapse progress to uncurable metastatic disease. Therefore, alternative treatment modalities are needed both in the situation of PSA recurrence and in hormone‐refractory disease. Dendritic cells (DC) are the most powerful antigen‐presenting cells, able to prime naïve T‐cells and to break peripheral tolerance and thus induce tumor immune responses. More than 400 prostate cancer patients have been treated with DC‐based immunotherapy to date, and immune responses have been reported in two‐thirds of these, resulting in clinical responses in almost half of the patients treated. Most responses, however, were modest and transient. Therefore, mechanisms of treatment failure and possibilities to improve vaccination efficacy are being discussed.

Semiquantitative analysis of Th1 and Th2 cytokine expression in CD3+, CD4+, and CD8+ renal-cell-carcinoma-infiltrating lymphocytes.

Abstract The mRNA expression of Th1 and Th2 cytokines was compared in freshly isolated CD3+ tumor-infiltrating lymphocytes (CD3+ TIL) and in autologous CD3+ peripheral blood lymphocytes (CD3+ PBL) obtained simultaneously from 20 patients with renal cell carcinomas (RCC). In addition cytokine expression was compared in CD4+ TIL and CD8+ TIL from another group of 20 patients with RCC. TIL were isolated from mechanically disaggregated tumor material and PBL from peripheral blood by gradient centrifugation and subsequent selection with anti-CD3, anti-CD4 or anti-CD8 magnetic beads. In these pure lymphocyte preparations the constitutive expression of interleukin-1 (IL-1), IL-2, IL-10, interferon γ (IFN), and tumor necrosis factor α (TNF) was determined by using a polymerase-chain-reaction-assisted mRNA amplification assay. In the CD3+ TIL, levels of mRNA for IFN, IL-10, IL-1 and TNF were significantly higher than in the autologous CD3+ PBL whereas IL-2 expression was rather low and did not differ in the two populations. Comparison of cytokine mRNA expression in CD4+ TIL and simultaneously obtained CD8+ TIL revealed a significantly higher expression of IFN in the CD8+ cells. These data reflect an in vivo activation of RCC-infiltrating lymphocytes at the mRNA level with respect to the Th1 as well as the Th2 immune response. Th1 activation seems to be most evident in the CD8+ TIL.