Management of patients with hormone refractory prostate cancer

Antioxidant and Cytotoxic Activities of Kudzu Roots and Soy Molasses against Pediatric Tumors and Phytochemical Analysis of Isoflavones Using HPLC-DAD-ESI-HRMS

Pediatric solid tumors (PSTs) are life-threatening and can lead to high morbidity and mortality rates in children. Developing novel remedies to treat these tumors, such as glioblastoma multiforme and sarcomas, such as osteosarcoma, and rhabdomyosarcoma, is challenging, despite immense attempts with chemotherapeutic or radiotherapeutic interventions. Soy (Glycine max) and kudzu roots (KR) (Pueraria spp.) are well-known phytoestrogenic botanical sources that contain high amounts of naturally occurring isoflavones. In the present study, we investigated the antioxidant and cytotoxic effects of the extracts of KR and soy molasses (SM) against PSTs. The green extraction of isoflavones from KR and SM was performed using natural deep eutectic solvents. The extracts were subsequently analyzed by high-performance liquid chromatography (HPLC)-diode array detector (DAD) coupled with high-resolution (HR) mass spectrometry (MS), which identified 10 isoflavones in KR extracts and 3 isoflavones in the SM extracts. Antioxidant and cytotoxic activities of KR and SM extracts were assessed against glioblastoma multiforme (A-172), osteosarcoma (HOS), and rhabdomyosarcoma (Rd) cancer cell lines. The KR and SM extracts showed satisfactory cytotoxic effects (IC₅₀) against the cancer cell lines tested, particularly against Rd cancer cell lines, in a dose-dependent manner. Antioxidant activity was found to be significantly (p ≤ 0.05) higher in KR than in SM, which was consistent with the results of the cytotoxic activity observed with KR and SM extracts against glioblastoma and osteosarcoma cells. The total flavonoid content and antioxidant activities of the extracts were remarkably attributed to the isoflavone content in the KR and SM extracts. This study provides experimental evidence that HPLC-ESI-HRMS is a suitable analytical approach to identify isoflavones that exhibit potent antioxidant and anticancer potential against tumor cells, and that KR and SM, containing many isoflavones, can be a potential alternative for health care in the food and pharmaceutical industries.

High-dose calcitriol, docetaxel and zoledronic acid in patients with castration-resistant prostate cancer: a phase II study

INTRODUCTION

Docetaxel has become the standard chemotherapy for patients with castration-resistant prostate cancer (CRPC). We wanted to assess the efficacy and safety of a weekly high-dose calcitriol, docetaxel and zoledronic acid combination in CRPC.

PATIENTS AND METHODS

Thirty patients were enrolled to receive calcitriol 0.5 µg/kg orally in 4 divided doses over 4 h on day 1 of each treatment week, docetaxel 36 mg/m(2) i.v. infusion on day 2 of each treatment week and zoledronic acid 4 mg i.v. on day 2 of the first and fifth week of each cycle. Treatment was administered weekly for 6 consecutive weeks on an 8-week cycle.

RESULTS

Out of 23 evaluable patients, there was a response of prostate-specific antigen (PSA) in 11 patients (47.8%); 6 (26.1%) had a stable PSA level for a median of 4.2 months. The median survival time was 15 months (95% confidence interval 13.9-16.1 months). The regimen was generally tolerated; anemia was the only grade 3/4 hematological toxicity in 2 patients.

CONCLUSIONS

This regimen was tolerated, and half of the patients had a PSA response. Although our response rates are inferior to some studies using docetaxel, we believe our response rates are acceptable knowing that we are treating CRPC, which still has variable outcomes.

The curcumin analog ca27 down-regulates androgen receptor through an oxidative stress mediated mechanism in human prostate cancer cells

BACKGROUND

The androgen receptor (AR) plays a critical role in prostate cancer development and progression. Therefore, the inhibition of AR function is an established therapeutic intervention. Since the expression of the AR is retained and often increased in progressive disease, AR protein down-regulation is a promising therapeutic approach against prostate cancer. We show here that the curcumin analog 27 (ca27) down-regulates AR expression in several prostate cancer cell lines.

METHODS

ca27 at low micromolar concentrations was tested for its effect on AR expression, AR activation, and induction of oxidative stress in human LNCaP, C4-2, and LAPC-4 prostate cancer cells.

RESULTS

ca27 induced the down-regulation of AR protein expression in LNCaP, C4-2, and LAPC-4 cells within 12 hr. Further, ca27 led to the rapid induction of reactive oxygen species (ROS). To further support this finding, ca27 treatment led to the activation of the cellular redox sensor NF-E2-related factor 2 (Nrf2) and the induction of the Nrf2-regulated genes NAD(P)H quinone oxidoreductase 1 and aldoketoreductase 1C1. We show that ROS production preceded AR protein loss and that ca27-mediated down-regulation of the AR was attenuated by the antioxidant, N-acetyl cysteine.

CONCLUSIONS

ca27 induces ROS and mediates AR protein down-regulation through an oxidative stress mechanism of action. Our results suggest that ca27 represents a novel agent for the elucidation of mechanisms of AR down-regulation, which could lead to effective new anti-androgenic strategies for the treatment of advanced prostate cancer.

Satraplatin: leading the new generation of oral platinum agents

BACKGROUND

In recent years, JM-216/satraplatin (GPC Biotech, Inc.) has emerged as a novel oral platinum analogue with a better toxicity profile than cisplatin. Since satraplatin is more hydrophobic than cisplatin or oxaliplatin, it appears to demonstrate efficacy in cisplatin-resistant cell lines. The preclinical and clinical evaluation of satraplatin stimulated this review of the pharmacology and clinical trial data of this agent.

METHODS

A literature review was conducted in the MEDLINE database from 1985 to present using the keywords 'satraplatin' or 'JM-216'. The abstracts regarding satraplatin reported at the 2007 - 2009 American Society of Clinical Oncology meetings were also reviewed.

RESULTS/CONCLUSION

Satraplatin has a favorable toxicity profile, and appears to have clinical activity against a variety of malignancies such as breast, prostate and lung cancer. The oral route of administration and the intermittent schedule makes it very convenient for clinical use. Despite this, a FDA-approved indication has not yet been achieved. The only Phase III trial with satraplatin was conducted in pretreated metastatic castrate-resistant prostate cancer (CRPC), revealing an improvement in progression-free survival but no overall survival benefit. Future development would have to include designing trials in docetaxel-refractory metastatic CRPC, or in other malignancies where cisplatin is of benefit.

Diethylstilbestrol glutamate as a potential substrate for ADEPT

The combination of systemic toxicity, water insolubility and a labile chemical structure has limited the clinical use of diethylstilbestrol (DES) 1 for the treatment of prostate cancer. To determine if DES could potentially be a prodrug substrate for the pre-targeting strategy known as antibody directed enzyme prodrug therapy (ADEPT), the DES-glutamate 5 was prepared. The synthesis required the activation of the bis-t-butyl glutamate ester 2 to the isocyanate 3 followed by addition of DES 1. The desired DES-glutamate 5 was water-soluble and upon incubation with carboxypeptidase G2 (CPG2) underwent carbamate cleavage to give DES 1. A control reaction in the absence of CPG2 demonstrated that the enzyme was necessary for rapid glutamate cleavage to give DES 1. HPLC analysis was required to follow the reaction of DES-glutamate 5 with CPG2. These preliminary results suggest that it may be possible to examine an ADEPT strategy for DES provided enzymatic kinetics can be measured.

[Hormone-refractory prostate cancer]

Hormone-refractory prostate cancer is an advanced stage of the metastatic disease; it has a poor prognosis and a short median survival, about 9 to 18 months. The current article is based on a literature review regarding the prognostic factors and medical treatments, with a focus on recent advances in chemotherapy. With the use of docetaxel that increases the median survival of this disease and improves the symptoms, new clinical protocols have been developed, with promising results; these protocols propose a combination with calcitriol or antiangiogenic agents. Supportive care is also an important part of the treatment due to the high level of bone involvement and its consequences. Such recent advances constitute a real progress in the management of prostate cancer, namely the pharmacological combinations with a promising efficacy and little toxicity.

Hormone-Refractory Prostate Cancer: A Shifting Paradigm in Treatment

Prostate cancer, the most common male cancer, affects one in eight American men. Risk factors for the disease include increased age, race, and family history of prostate cancer. To date, surgery, radiation, and hormonal therapy have been the mainstays of treatment. In the past, chemotherapy served only a palliative role for men with prostate cancer and failed to produce a survival advantage or any significant measurable disease response. However, for the first time, docetaxel-based regimens have demonstrated improved survival in men with hormone-refractory prostate cancer in two different, large, phase III studies. Additionally, a number of novel agents are being developed with the hope that treatment for men with hormone-refractory prostate cancer will be improved. Oncology nurses provide critical symptom management strategies as well as education to men with prostate cancer and their partners. Therefore, maintaining current state of the knowledge about best practices and treatment for prostate cancer is crucial. This, in turn, directs efforts to educate patients and family members about treatments and management of side effects.

Human osteocalcin: a strong promoter for nitric oxide synthase gene therapy, with specificity for hormone refractory prostate cancer

BACKGROUND

Gene therapy has been identified as a promising treatment strategy for hormone refractory prostate cancer (HRPC). We report, for the first time, the use of the human osteocalcin (hOC) promoter to control inducible nitric oxide synthase (iNOS) transgene expression in HRPC.

METHODS

Human prostate carcinoma cells (PC3, DU145, LNCaP), colon cancer cells (HT29) and human microvascular endothelial cells (HMEC-1) were transfected in vitro with constitutively driven CMV/iNOS or hOC/iNOS plasmid DNA by cationic lipid vector. End points of these experiments were Western blotting, NO(.) generation using the Greiss test to measure accumulated nitrite, and clonogenic assay.

RESULTS

Transfection of the hOC/iNOS plasmid increased iNOS protein and total nitrite levels in PC3 and DU145 cells, but not LNCaP or HT29. Transfection with CMV/iNOS or hOC/iNOS resulted in no additional cytotoxicity in androgen-dependent LNCaP cells or in the non-prostate cell lines. However, transfection with either construct resulted in a greatly reduced cell survival (to 10-20%) in the androgen-independent PC3 and DU145 cell lines.

CONCLUSIONS

Utilising the tumour-type specific properties of the hOC promoter in tandem with the iNOS gene, we have demonstrated target cell specificity, and transgene activation, in the androgen-independent prostate cancer cell lines (PC3 and DU145), an effect absent in normal and androgen-dependent cells. Furthermore, the levels of NO(.) generated are comparable with those seen generated with constitutively (CMV)-driven iNOS. The data obtained from this study provide a basis for future development of hOC/iNOS gene therapy.

A systematic review of the effectiveness of docetaxel and mitoxantrone for the treatment of metastatic hormone-refractory prostate cancer

A systematic review was performed to evaluate the clinical effectiveness of docetaxel in combination with prednisolone (docetaxel is licensed in the UK for use in combination with prednisone or prednisolone for the treatment of patients with metastatic hormone-refractory prostate cancer. Prednisone is not used in the UK, but it is reasonable to use docetaxel plus prednisone data in this review of docetaxel plus prednisolone) for the treatment of metastatic hormone-refractory prostate cancer. A scoping search identified a trial of docetaxel plus prednisone vs mitoxantrone plus prednisone, but did not identify any trials comparing docetaxel plus prednisolone/prednisone with any other treatments. Therefore, we considered additional indirect evidence that would enable a comparison of docetaxel plus prednisolone/prednisone with other chemotherapy regimens and active supportive care. Systematic searching (upto April 2005) identified seven randomised controlled trials. One large well-conducted trial assessed docetaxel plus prednisone vs mitoxantrone plus prednisone; this showed statistically significant improvements with 3-weekly docetaxel in terms of overall survival, quality of life, pain response and PSA decline. Two other chemotherapy regimens that included docetaxel with estramustine also showed improved outcomes in comparison with mitoxantrone plus prednisone. Three trials that compared mitoxantrone plus corticosteroids with corticosteroids alone were identified and their results for overall survival combined, which showed very little difference between the two groups. The addition of clodronate to mitoxantrone plus prednisone showed no significant differences in comparison with mitoxantrone plus prednisone alone. The evidence suggests that chemotherapy regimens containing 3-weekly docetaxel are superior to mitoxantrone or corticosteroids alone.

Satraplatin: an orally available platinum analog for the treatment of cancer

Satraplatin is a novel, orally bioavailable, platinum anticancer drug. Platinum analogs form the mainstay of treatment for a number of cancers, including lung, ovarian, colorectal and head and neck cancer. A disadvantage of the currently marketed platinum analogs is that they must all be administered via intravenous infusion. In addition, their utility is often limited by toxicity, particularly neurotoxicity, ototoxicity and renal toxicity. Satraplatin has preclinical antitumor activity comparable with that of cisplatin and, clinically, has a more manageable side-effect profile. Satraplatin is active in lung, ovarian and prostate cancer, and appears to have good efficacy in combination with radiation for lung and head and neck cancer. Preclinical data suggest it may also be effective for the treatment of certain cisplatin-refractory tumors. A large, randomized Phase III trial is currently evaluating satraplatin in combination with prednisone for the treatment of patients with hormone-refractory prostate cancer whose disease has progressed following prior systemic therapy. Positive results from this trial would support regulatory approval for satraplatin for this indication. The availability of an active oral platinum agent, such as satraplatin, with few of the serious toxicities associated with traditional intravenous platinum compounds makes satraplatin an alternative to other platinum agents and a new treatment option in the oncologist's armamentarium.