Weekly administration of docetaxel in combination with estramustine and celecoxib in patients with advanced hormone-refractory prostate cancer: final results from a phase II study

The Potential Preventive and Therapeutic Roles of NSAIDs in Prostate Cancer

Prostate cancer (PC) is the second most common type of cancer and the leading cause of death among men worldwide. Preventing the progression of cancer after treatments such as radical prostatectomy, radiation therapy, and hormone therapy is a major concern faced by prostate cancer patients. Inflammation, which can be caused by various factors such as infections, the microbiome, obesity and a high-fat diet, is considered to be the main cause of PC. Inflammatory cells are believed to play a crucial role in tumor progression. Therefore, nonsteroidal anti-inflammatory drugs along with their effects on the treatment of inflammation-related diseases, can prevent cancer and its progression by suppressing various inflammatory pathways. Recent evidence shows that nonsteroidal anti-inflammatory drugs are effective in the prevention and treatment of prostate cancer. In this review, we discuss the different pathways through which these drugs exert their potential preventive and therapeutic effects on prostate cancer.

Targeting androgen-independent pathways: new chances for patients with prostate cancer?

Androgen deprivation therapy (ADT) is the mainstay treatment for advanced prostate cancer (PC). Most patients eventually progress to a condition known as castration-resistant prostate cancer (CRPC), characterized by lack of response to ADT. Although new androgen receptor signaling (ARS) inhibitors and chemotherapeutic agents have been introduced to overcome resistance to ADT, many patients progress because of primary or acquired resistance to these agents. This comprehensive review aims at exploring the mechanisms of resistance and progression of PC, with specific focus on alterations which lead to the activation of androgen receptor (AR)-independent pathways of survival. Our work integrates available clinical and preclinical data on agents which target these pathways, assessing their potential clinical implication in specific settings of patients. Given the rising interest of the scientific community in cancer immunotherapy strategies, further attention is dedicated to the role of immune evasion in PC.

Combination of Lipitor and Celebrex inhibits prostate cancer VCaP cells in vitro and in vivo

BACKGROUND/AIM

Lipitor is a cholesterol-lowering drug and Celebrex is a Cyclooxygenase-2 inhibitor. We investigated the effects of Lipitor and Celebrex on human prostate cancer VCaP cells cultured in vitro and grown as orthotopic xenograft tumors in SCID mice.

MATERIALS AND METHODS

Apoptosis was measured by morphological assessment and caspase-3 assay. Nuclear factor-kappa B (NF-κB) activation was determined by luciferase reporter assay. B-cell lymphoma-2 (Bcl2) was measured by western blotting and immunohistochemistry. Orthotopic prostate tumors were monitored by the IVIS imaging system.

RESULTS

the combination of Lipitor and Celebrex had stronger effects on the growth and apoptosis of VCaP cells than did either drug alone. The combination more potently inhibited activation of NFκB and expression of Bcl2 than either drug alone. The growth of orthotopic VCaP prostate tumors was strongly inhibited by treatment with the drug combination.

CONCLUSION

Administration of Lipitor and Celebrex in combination may be an effective strategy for inhibiting the growth of prostate cancer.

Regression of prostate tumors upon combination of hormone ablation therapy and celecoxib in vivo

BACKGROUND

Hormonal ablation is the standard of treatment for advanced androgen-dependent prostate cancer. Although tumor regression is usually achieved at first, the cancer inevitably evolves toward androgen-independence, in part because of the development of mechanisms of resistance and in part because at the tissue level androgen withdrawal is not fully attained. Current research efforts are focused on new therapeutic strategies that will increase the effectiveness of androgen withdrawal and delay recurrence. We used a syngeneic pseudo-orthotropic mouse model of prostate cancer to test the efficacy of combining androgen withdrawal with FDA-approved COX-2 inhibitor celecoxib.

METHODS

GFP-tagged TRAMP-C2 cells were co-implanted with prostate tissue in the dorsal chamber model and tumors were allowed to establish and vascularize. Tumor growth and angiogenesis were monitored in real-time using fluorescent intravital microscopy (IVM). Androgen withdrawal in mice was achieved using surgical castration or chemical hormonal ablation, alone or in combination with celecoxib (15 mg/kg, twice daily).

RESULTS

Celecoxib alone decreased the growth of prostate tumors mostly by inducing mitotic failure, which resulted in increased apoptosis. Surprisingly, celecoxib did not possess significant angiostatic activity. Surgical or chemical castration prevented the growth of prostate tumors and this, on the other hand, was associated with disruption of the tumor vasculature. Finally, androgen withdrawal combined with celecoxib caused tumor regression through decreased angiogenesis and increased mitosis arrest and apoptosis.

CONCLUSION

Celecoxib, a relatively safe COX-2-selective anti-inflammatory drug, significantly increases the efficacy of androgen withdrawal in vivo and warrants further investigation as a complement therapy for advanced prostate cancer.

Synthesis and antitumor properties of selenocoxib-1 against rat prostate adenocarcinoma cells

Hormone refractory prostate cancer poses a huge problem and standard of care chemotherapy has not been very successful. We used a novel strategy to combine properties of 2 well-studied class of compounds (selenium and COX-2 inhibitor) and examined the resulting effectiveness against prostate cancer. Bearing in mind that sulfonamide moiety and pyrazole ring is important for the proapoptotic activity of Celecoxib, we synthesized a selenium derivative, Selenocoxib-1, by modifying Celecoxib at position 3 of the pyrazole ring. The PAIII cells derived from a metastatic prostate tumor that arose spontaneously in a Lobund-Wistar (LW) rat were used to examine the efficacy of Selenocoxib-1 in vitro. In addition, human metastatic prostate cancer cells, PC-3M, were tested for antitumor effect of Selenocoxib-1 in vitro. The IC(50) in PAIII and PC-3M cells for Selenocoxib-1 was about 5 microM, while for Celecoxib it was more than 20 microM. Selenocoxib-1 induced apoptosis in a dose-dependent manner in the PAIII cells. COX-2 expression in PAIII cells was downregulated by Celecoxib and Selenocoxib-1 at 20 and 5 microM, respectively; the COX-2 activity was, however, not affected by Selenocoxib-1. Following treatment with Selenocoxib-1, PAIII cells resulted in dose-dependent decrease in HIF-1alpha, p-AKT and Bcl-2 levels. A reduction in weights was observed in subcutaneous tumors produced by PAIII cells pretreated with Selenocoxib-1 as compared to Celecoxib in LW rats. Further, following 1 week Selenocoxib-1 treatment of PAIII tumors resulted in significant reduction of tumor weights. This study demonstrates that Selenocoxib-1 is more effective against prostate cancer than Celecoxib.

Molecular and traditional chemotherapy: a united front against prostate cancer

Castrate resistant prostate cancer (CRPC) is essentially incurable. Recently though, chemotherapy demonstrated a survival benefit ( approximately 2months) in the treatment of CRPC. While this was a landmark finding, suboptimal efficacy and systemic toxicities at the therapeutic doses warranted further development. Smart combination therapies, acting through multiple mechanisms to target the heterogeneous cell populations of PC and with potential for reduction in individual dosing, need to be developed. In that, targeted molecular chemotherapy has generated significant interest with the potential for localized treatment to generate systemic efficacy. This can be further enhanced through the use of oncolytic conditionally replicative adenoviruses (CRAds) to deliver molecular chemotherapy. The prospects of chemotherapy and molecular-chemotherapy as single and as components of combination therapies are discussed.

Phase II, randomized, placebo-controlled trial of neoadjuvant celecoxib in men with clinically localized prostate cancer: evaluation of drug-specific biomarkers

PURPOSE

Cyclooxygenase-2 (COX-2) is a potential pharmacologic target for the prevention of various malignancies, including prostate cancer. We conducted a randomized, double-blind trial to examine the effect of celecoxib on drug-specific biomarkers from prostate tissue obtained at prostatectomy.

PATIENTS AND METHODS

Patients with localized prostate cancer and Gleason sum > or = 7, prostate-specific antigen (PSA) > or = 15 ng/mL, clinical stage T2b or greater, or any combination with greater than 45% risk of capsular penetration were randomly assigned to celecoxib 400 mg by mouth twice daily or placebo for 4 to 6 weeks before prostatectomy. The primary end point was the difference in prostatic prostaglandin levels between the two groups. Secondary end points were differences in COX-1 and -2 expressions; oxidized DNA bases; and markers of proliferation, apoptosis and angiogenesis. Tissue celecoxib concentrations also were measured. Tertiary end points were drug safety and compliance.

RESULTS

Seventy-three patients consented, and 64 were randomly assigned and included in the intention-to-treat analysis. There were no treatment differences in any of the primary or secondary outcomes. Multivariable regression revealed that tumor tissue had significantly lower COX-2 expression than benign prostatic tissue (P = .01) and significantly higher levels of the proliferation marker Ki-67 (P < .0001). Celecoxib was measurable in prostate tissue of patients on treatment, demonstrating that celecoxib reached its target. Celecoxib was safe and resulted in only grade 1 toxicities.

CONCLUSION

Treatment with 4 to 6 weeks of celecoxib had no effect on intermediate biomarkers of prostate carcinogenesis, despite the achievement of measurable tissue levels. We caution against using celecoxib 400 mg twice daily as a preventive agent for prostate cancer in additional studies.

Anti-inflammatory drugs, antioxidants, and prostate cancer prevention

Prostate cancer may be the most common preventable cancer among men in the United States (US) and the rest of the developed world. Emerging insights into the molecular pathogenesis of prostate cancer suggest that damage to the prostate epithelium, potentially inflicted by a variety of exposures, triggers procarcinogenic inflammatory processes to promote disease development. In this milieu, the damaged epithelium may generate proliferative inflammatory atrophy (PIA) lesions, which may progress to prostatic intraepithelial neoplasia (PIN) or to prostate cancer. To attenuate prostatic carcinogenesis driven by chronic or recurrent prostate inflammation, rational chemoprevention has thus far featured anti-inflammatory drugs and antioxidants. Results from clinical trials of these approaches have been mixed, emphasizing the need for mechanistic studies of the contribution of inflammation to prostatic carcinogenesis, more extensive analyses of the pharmacology, including distribution of drugs into target tissue, and, rational development of biomarkers to identify patients that are most likely to respond to anti-inflammatory drugs and antioxidants (targeted chemoprevention), alone, or in combination (combination chemoprevention).

Targeted therapy for advanced prostate cancer: inhibition of the PI3K/Akt/mTOR pathway

A large number of novel therapeutics is currently undergoing clinical evaluation for the treatment of prostate cancer, and small molecule signal transduction inhibitors are a promising class of agents. These inhibitors have recently become a standard therapy in renal cell carcinoma and offer significant promise in prostate cancer. Through an understanding of the key pathways involved in prostate cancer progression, a rational drug design can be aimed at the molecules critical to cellular signaling. This may enable administration of selective therapies based on the expression of molecular targets, more appropriately individualizing treatment for prostate cancer patients. One pathway with a prominent role in prostate cancer is the PI3K/Akt/mTOR pathway. Current estimates suggest that PI3K/Akt/mTOR signaling is upregulated in 30-50% of prostate cancers, often through loss of PTEN. Molecular changes in the PI3K/Akt/mTOR signaling pathway have been demonstrated to differentiate benign from malignant prostatic epithelium and are associated with increasing tumor stage, grade, and risk of biochemical recurrence. Multiple inhibitors of this pathway have been developed and are being assessed in the laboratory and in clinical trials, with much attention focusing on mTOR inhibition. Current clinical trials in prostate cancer are assessing efficacy of mTOR inhibitors in combination with multiple targeted or traditional chemotherapies, including bevacizumab, gefitinib, and docetaxel. Completion of these trials will provide substantial information regarding the importance of this pathway in prostate cancer and the clinical implications of its targeted inhibition. In this article we review the data surrounding PI3K/Akt/mTOR inhibition in prostate cancer and their clinical implications.

Docetaxel and Estramustine for Prostate Cancer

The complexity of cancer chemotherapy requires that pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparing, dispensing, and administering antineoplastic therapy and to the agents, commercially available and investigational, used to treat malignant diseases.

Docetaxel in the management of prostate cancer: current standard of care and future directions

BACKGROUND

Advanced and metastatic prostate cancer continues to represent a significant healthcare burden. Since the publication of two randomized trials that showed significant survival and palliative benefits for men treated with docetaxel, this drug has become the treatment of choice for patients with metastatic castration resistant prostate cancer (CRPC).

OBJECTIVE

This review discusses the development and current use of docetaxel in metastatic CRPC, as well as future clinical applications.

METHODS

The current literature, meeting abstracts and ClinicalTrials.gov have been reviewed. The most relevant studies involving patients with prostate cancer receiving therapy with docetaxel, alone or in combination with other agents, have been summarised.

CONCLUSION

Docetaxel monotherapy is the approved treatment for patients with metastatic CRPC, and its association with other agents, such as targeted therapies, is currently under study. Several trials are currently ongoing to investigate the use of docetaxel in the early stages of disease, particularly in the neoadjuvant and adjuvant settings for patients with high-risk disease.

Cyclooxygenase-2 (COX-2): a molecular target in prostate cancer

Epidemiological studies provided the first evidence that COX may be involved in the pathogenesis of cancer. In the process of carcinogenesis and in the route of intracellular signalling during carcinogenesis, COX-2 expression may be a universal phenomenon. In general, COX-2 is up-regulated throughout the tumorigenic process, from early hyperplasia to metastatic disease. COX-2 has been reported to be constitutively overexpressed in a variety of malignancies and is frequently constitutively elevated in prostate carcinoma. COX-2 was consistently overexpressed in premalignant lesions such as prostatic intraepithelial neoplasia, and carcinoma. Cases are described with evolution of proliferative inflammatory atrophy of the prostate and prostate carcinoma. The increase of evidence implicating COX-2 in cancer has stimulated clinical trials to investigate the efficacy of selective COX-2 inhibitors in individuals at risk for human cancer. Regarding prostate carcinoma there is much direct or indirect evidence to support the use of COX-2 inhibitors in this disease. Trials using these drugs in familial adenomatous polyposis (FAP) and other patients with a high risk of colorectal carcinoma are ongoing.