Phase II trial of estramustine and etoposide in androgen-sensitive metastatic prostate carcinoma

Prognostication of prostate cancer based on TOP2A protein and gene assessment: TOP2A in prostate cancer

Background

TOP2A encodes for topoisomerase IIα, a nuclear enzyme that controls DNA topological structure and cell cycle progression. This enzyme is a marker of cell proliferation in normal and neoplastic tissues; however, little information is available about its expression in prostate cancer (PCa).

Methods

Immunohistochemistry (IHC) was automated using mouse monoclonal antibody against TOP2A (clone SWT3D1; DAKO, Carpenteria, CA, USA) at dilution 1:800 and Flex Plus detection system in autostainer 48Ultra (DAKO). FISH was performed using TOP2A (17q21)/ CEP17 probe kit (Kreateck Biotechnology, San Diego, CA, USA). Biochemical and pathological data from 193 patients with PCa were retrieved for the analysis, whose significance was considered when p < 0.05. Also, fractal analysis was performed in a subset of 20 randomly selected cases.

Results

TOP2A protein expression correlated with higher Gleason scores and higher levels of preoperative PSA (p = 0.018 and p = 0.011). Patients with higher levels of TOP2A presented shorter biochemical recurrence-free survival (BRFS) (p = 0.001). In multivariate analysis, we found that TOP2A remained an independent prognostic factor of BRFS, with a relative risk of 1.98 (p = 0.001; 95% CI, 1.338–2.93); thus, cases that expressed high levels of this enzyme had a shorter BRFS compared with TOP2A-negative or TOP2A-low cases. No alterations in TOP2A gene status nor correlation between FISH and IHC results were observed. Concerning fractal analysis, patients who expressed higher levels of TOP2A have angiolymphatic invasion and presented higher Gleason scores (p = 0.033 and p = 0.025, respectively). Also, patients with higher expression of TOP2A presented shorter BRFS (p = 0.001).

Conclusions

This is the first study to perform TOP2A protein and gene digital assessment and fractal analysis in association with BRFS in a large series of PCa. Also, we show that TOP2A gene copy number alterations are not observed in this type of tumor. So, higher protein expression of TOP2A is not related to gene amplification in PCa. Furthermore, TOP2A protein assessment has prognostic importance and, due to its relation with poor outcome, TOP2A IHC evaluation in the biopsy can represent an important tool for selecting the most suitable surgical and clinical approach for patients with PCa.

Enhanced antitumor efficacy of low-dose Etoposide with oncolytic herpes simplex virus in human glioblastoma stem cell xenografts

PURPOSE

Glioblastoma (GBM) inevitably recurs despite surgery, radiation, and chemotherapy. A subpopulation of tumor cells, GBM stem cells (GSC), has been implicated in this recurrence. The chemotherapeutic agent etoposide is generally reserved for treating recurrent tumors; however, its effectiveness is limited due to acute and cumulative toxicities to normal tissues. We investigate a novel combinatorial approach of low-dose etoposide with an oncolytic HSV to enhance antitumor activity and limit drug toxicity.

EXPERIMENTAL DESIGN

In vitro, human GBM cell lines and GSCs were treated with etoposide alone, oncolytic herpes simplex virus (oHSV) G47Δ alone, or the combination. Cytotoxic interactions were analyzed using the Chou-Talalay method, and changes in caspase-dependent apoptosis and cell cycle were determined. In vivo, the most etoposide-resistant human GSC, BT74, was implanted intracranially and treated with either treatment alone or the combination. Analysis included effects on survival, therapy-associated adverse events, and histologic detection of apoptosis.

RESULTS

GSCs varied in their sensitivity to etoposide by over 50-fold in vitro, whereas their sensitivity to G47Δ was similar. Combining G47Δ with low-dose etoposide was moderately synergistic in GSCs and GBM cell lines. This combination did not enhance virus replication, but significantly increased apoptosis. In vivo, the combination of a single cycle of low-dose etoposide with G47Δ significantly extended survival of mice-bearing etoposide-insensitive intracranial human GSC-derived tumors.

CONCLUSIONS

The combination of low-dose etoposide with G47Δ increases survival of mice-bearing intracranial human GSC-derived tumors without adverse side effects. These results establish this as a promising combination strategy to treat resistant and recurrent GBM.

Inhibition of tumor angiogenesis by oral etoposide

The chemotherapeutic agent etoposide is a topoisomerase II inhibitor widely used for cancer therapy. Low-dose oral etoposide, administered at close regular intervals, has potent anti-tumor activity in patients who are refractory to intravenous etoposide; however, the mechanism remains unclear. Since endothelial cells may be more sensitive than tumor cells to chemotherapy agents, we determined the effects of etoposide alone and in combination with oral cyclooxygenase-2 inhibitors and peroxisome-proliferator activated receptor γ ligands on angiogenesis and tumor growth in xenograft tumor models. Optimal anti-angiogenic (metronomic) and anti-tumor doses of etoposide on angiogenesis, primary tumor growth and metastasis were established alone and in combination therapy. Etoposide inhibited endothelial and tumor cell proliferation, decreased vascular endothelial growth factor (VEGF) production by tumor cells and suppressed endothelial tube formation at non-cytotoxic concentrations. In our in vivo studies, oral etoposide inhibited fibroblast growth factor 2 and VEGF-induced corneal neovascularization, VEGF-induced vascular permeability and increased levels of the endogenous angiogenesis inhibitor endostatin in mice. In addition, etoposide inhibited Lewis lung carcinoma (LLC) and human glioblastoma (U87) primary tumor growth as well as spontaneous lung metastasis in a LLC resection model. Furthermore, etoposide had synergistic anti-tumor activity in combination with celecoxib and rosiglitazone, which are also oral anti-angiogenic and anti-tumor agents. Etoposide inhibits angiogenesis in vitro and in vivo by indirect and direct mechanisms of action. Combining etoposide with celecoxib and rosiglitazone increases its efficacy and merits further investigation in future clinical trials to determine the potential usefulness of etoposide in combinatory anti-angiogenic chemotherapy.

Phase II trial of docetaxel with rapid androgen cycling for progressive noncastrate prostate cancer

PURPOSE

We evaluated rapid androgen cycling in combination with docetaxel for men with progressive noncastrate prostate cancers.

PATIENTS AND METHODS

Noncastrate patients with 150 ng/dL) and an undetectable prostate-specific antigen (PSA;

RESULTS

A higher proportion of patients achieved the undetectable PSA outcome at 18 months in cohort 2 relative to cohort 1 (13% v 0%). The 16% incidence of febrile neutropenia was higher than that observed in patients was castration-resistant disease, which may have been related to a 50% reduction in overall docetaxel clearance in the noncastrate group. There was no alteration in CYP3A4 activity (P = .87) or docetaxel clearance (P = .88) between cycles.

CONCLUSION

The undetectable PSA end point allows for a rapid screening of interventions for further study. Increasing the number of docetaxel cycles after a shorter period of testosterone repletion, and a longer duration of testosterone depletion, increased the proportion of men who achieved an undetectable PSA. The higher-than-expected incidence of febrile neutropenia may have been related to the reduced overall docetaxel clearance in patients with noncastrate versus castrate testosterone levels.

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MESH Headings

• Adult
• Aged
• Aged, 80 and over
• Antineoplastic Combined Chemotherapy Protocols/administration & dosage
• Cytochrome P-450 CYP3A
• Cytochrome P-450 Enzyme System/metabolism
• Docetaxel
• Humans
• Leuprolide/administration & dosage
• Male
• Middle Aged
• Prostate-Specific Antigen/blood
• Prostatic Neoplasms/drug therapy
• Prostatic Neoplasms/metabolism
• Taxoids/administration & dosage
• Taxoids/pharmacokinetics
• Testosterone/administration & dosage
• Testosterone/metabolism

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Grants

• P30 CA006973-48 NCI NIH HHS
• P30 CA006973 NCI NIH HHS
• P50-CA92629 NCI NIH HHS
• P50 CA092629 NCI NIH HHS
• PC051382 NCI NIH HHS

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Affiliation(s)

Dana Rathkopf Genitourinary Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York, USA and Department of Medicine, Joan and Sanford Weill College of Medicine, New York, New York, USA
Michael A. Carducci Prostate Cancer Program, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
Michael J. Morris Genitourinary Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York, USA and Department of Medicine, Joan and Sanford Weill College of Medicine, New York, New York, USA
Susan F. Slovin Genitourinary Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York, USA and Department of Medicine, Joan and Sanford Weill College of Medicine, New York, New York, USA
Mario A. Eisenberger Prostate Cancer Program, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
Roberto Pili Prostate Cancer Program, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
Samuel R. Denmeade Prostate Cancer Program, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
Moshe Kelsen Genitourinary Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York, USA and Department of Medicine, Joan and Sanford Weill College of Medicine, New York, New York, USA
Tracy Curley Genitourinary Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York, USA and Department of Medicine, Joan and Sanford Weill College of Medicine, New York, New York, USA
Regina Priet Prostate Cancer Program, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
Connie Collins Prostate Cancer Program, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA
Martin Fleisher Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
Glenn Heller Department of Clinical Chemistry, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
Sharyn D. Baker Pharmaceutical Sciences Department, St. Jude Children’s Research Hospital, Memphis, TN, USA
Howard I. Scher Genitourinary Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York, USA and Department of Medicine, Joan and Sanford Weill College of Medicine, New York, New York, USA

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Retinoblastoma tumor suppressor status is a critical determinant of therapeutic response in prostate cancer cells

The retinoblastoma tumor suppressor protein (RB), a critical mediator of cell cycle progression, is functionally inactivated in the majority of human cancers, including prostatic adenocarcinoma. The importance of RB tumor suppressor function in this disease is evident because 25% to 50% of prostatic adenocarcinomas harbor aberrations in RB pathway. However, no previous studies challenged the consequence of RB inactivation on tumor cell proliferation or therapeutic response. Here, we show that RB depletion facilitates deregulation of specific E2F target genes, but does not confer a significant proliferative advantage in the presence of androgen. However, RB-deficient cells failed to elicit a cytostatic response (compared with RB proficient isogenic controls) when challenged with androgen ablation, AR antagonist, or combined androgen blockade. These data indicate that RB deficiency can facilitate bypass of first-line hormonal therapies used to treat prostate cancer. Given the established effect of RB on DNA damage checkpoints, these studies were then extended to determine the impact of RB depletion on the response to cytotoxic agents used to treat advanced disease. In this context, RB-deficient prostate cancer cells showed enhanced susceptibility to cell death induced by only a selected subset of cytotoxic agents (antimicrotubule agents and a topoisomerase inhibitor). Combined, these data indicate that RB depletion dramatically alters the cellular response to therapeutic intervention in prostate cancer cells and suggest that RB status could potentially be developed as a marker for effectively directing therapy.

Phase II Evaluation of Oral Estramustine, Oral Etoposide, and Intravenous Paclitaxel in Patients with Hormone-Sensitive Prostate Adenocarcinoma

PURPOSE

The primary objective of this study was to assess the feasibility and efficacy of administering etoposide/estramustine/paclitaxel in hormone-sensitive metastatic prostate cancer responding to hormonal therapy.

PATIENTS AND METHODS

Eligible patients had metastatic prostate cancer and had received combined androgen blockade for 6-8 months with a > or = 80% decrease in prostate-specific antigen from pretreatment. They received 4 cycles of chemotherapy consisting of estramustine 280 mg orally 3 times daily, etoposide 50 mg/m2 orally on days 1-14, and paclitaxel 135 mg/m2 intravenously for 1 hour on day 2 of each 21-day cycle and were then followed until time to treatment failure (TTF).

RESULTS

Twenty-six patients were evaluable for response and toxicity. Median TTF was 21.7 months (range, 11.9-64.5 months; 95% confidence interval, 15.3-26.2 months). Median survival from time of initiation of hormone therapy was 5.1 years. Neutropenia was the most common grade 3/4 toxicity, occurring in 3 patients. Significant toxicities were limited to nausea, diarrhea, and febrile neutropenia in 3 patients, respectively.

CONCLUSION

The administration of paclitaxel/estramustine/etoposide in this setting is feasible and well tolerated. Although the TTF of 21.7 months by prostate-specific antigen criteria is similar to historical controls in the emergence of clinically evident androgen-independent disease after starting hormone therapy, direct comparisons cannot be made. More trials are needed to investigate the timing of chemotherapy in patients with prostate cancer.

Modulation of aflatoxin toxicity and biomarkers by lycopene in F344 rats

Modulation by lycopene of aflatoxin B(1) (AFB(1))-induced toxic effects, metabolism, and metabolic activations was studied in young F344 rats. Animals were pretreated orally with either corn oil (control group) or lycopene [100 mg/kg body weight (b.w.), intervention group] 5 days/week for 2 weeks. Control animals were then treated daily with AFB(1) (250 microg/kg b.w) alone. Intervention animals were administered lycopene (100 mg/kg b.w.) at 1 h following a daily treatment with AFB(1) (250 mug/kg b.w.). Pretreatment and intervention with lycopene significantly reduced the toxic effect caused by AFB(1) and greatly modulated AFB(1) metabolism and metabolic activation. Urinary excretion of AFB(1) phase 1 metabolites, AFM(1), AFQ(1), and AFP(1), was significantly decreased in lycopene-treated animals. Formation of serum AFB(1)-albumin adducts was also significantly reduced. The rate of reduction was from approximately 30% on day 1 (p<0.05) to 67.7% on day 15 (p<0.001). Lycopene intervention also significantly reduced formation of AFB(1)-DNA adducts in liver compared to control animals, with the highest reduction (52.7%) occurring on day 3 (p<0.05). Levels of AFB(1)-N(7)-guanine excreted in urine were also significantly decreased. Urinary excretion of the phase 2 detoxification metabolite, AFB(1)-mecapturic acid, was significantly increased in lycopene-intervened animals. AFB(1)-induced urinary excretion of 8-hydroxydeoxyguanosine was also reduced to 50% on day 7 after lycopene intervention. Collectively, these results suggest that inhibition of phase 1 metabolism and metabolic activation, as well as induction of phase 2 detoxification enzyme activity are the potential mechanisms for the chemopreventive effects of lycopene.

Changing perspectives of the role of chemotherapy in advanced prostate cancer

The use of cytotoxic chemotherapy in advanced prostate adenocarcinoma has been validated by the recent demonstration of survival benefit in two large randomized phase III trials. Before publication of these landmark trials, SWOG 9916 and TAX 327, no chemotherapeutic regimen had shown survival benefit in the treatment of androgen independent prostate cancer (AIPC). These trials provide new encouragement for the use of chemotherapy in all stages of disease. Improved communication between medical and urologic oncologists and early patient referral for clinical trial participation remains essential for identifying new chemotherapeutic regimens with improved activity in AIPC and for defining the role of chemotherapy in earlier-stage disease. This article discusses the role of chemotherapy as the current standard of care for the treatment of AIPC and provides a historical perspective of the trials that preceded the development of current docetaxel-based regimens.

Androgen receptor activity is inhibited in response to genotoxic agents in a p53-independent manner

The androgen receptor (AR) is fundamental to androgen signalling within the prostate gland, and deregulation of its activity is frequently linked to the development of prostate cancer. Advanced prostate cancer is often treated with chemotherapy and most of these drugs exert their function by generating genotoxic stress such as DNA damage. We have investigated here the effects of genotoxic agents used in chemotherapeutic regimens on AR function and expression. We have discovered that endogenous AR activity in LNCaP cells is inhibited in response to the chemotherapeutic agents etoposide and cisplatin. This loss of AR activity is not caused by a change in cell cycle distribution, a change in subcellular localisation of the AR nor by induction of apoptosis. In addition, we found that inhibition of AR activity in response to genotoxic stress is independent of p53 function. Interestingly, our studies revealed that genotoxic stress inhibits the hormone-stimulated recruitment of AR to androgen response elements. Thus, we report for the first time a mechanism by which the AR activity is inhibited in response to different chemotherapeutic agents.