Non-hormonal systemic therapy in men with hormone-refractory prostate cancer and metastases: a systematic review from the Cancer Care Ontario Program in Evidence-based Care's Genitourinary Cancer Disease Site Group

Senescence, Necrosis, and Apoptosis Govern Circulating Cell-free DNA Release Kinetics

The kinetics of circulating cell-free DNA (cfDNA) release may provide a real-time assessment of induced cell death. However, there is a limited understanding of the underlying biological rationale for cfDNA release following distinct treatments and cell death mechanisms. Here, we uncover a complex interplay between apoptosis, necrosis, and senescence in determining cfDNA release kinetics. Utilizing multiple in vitro and in vivo preclinical models, we show how cfDNA release is modulated through a combination of apoptotic and senescent triggers and inhibitors. Interestingly, we identify treatment-induced senescence as a previously unrecognized determinant of cfDNA kinetics that can counteract its release. Necrosis is the predominant cell death mechanism that consistently contributes to cfDNA release in response to ionizing radiation, and, surprisingly, apoptosis plays a comparatively minor role in some tumors. Based on our results, we propose a model to explain cfDNA release from cells over time, with important implications for future studies.

PRMT5 as a druggable target for glioblastoma therapy

Background

In spite of standard multimodal therapy consisting of surgical resection followed by radiation and concurrent chemotherapy, prognosis for glioblastoma (GBM) patients remains poor. The identification of both differentiated and undifferentiated "stem cell like" populations in the tumor highlights the significance of finding novel targets that affect the heterogeneous tumor cell population. Protein arginine methyltransferase 5 (PRMT5) is one such candidate gene whose nuclear expression correlates with poor survival and has been reported to be required for survival of differentiated GBM cells and self-renewal of undifferentiated GBM cells. In the current study we screened the specificity and efficacy of 4 novel PRMT5 inhibitors in the treatment of GBM.

Methods

Efficacies of these inhibitors were screened using an in vitro GBM neurosphere model and an in vivo intracranial zebrafish model of glioma. Standard molecular biology methods were employed to investigate changes in cell cycle, growth, and senescence.

Results

In vitro and in vivo studies revealed that among the 4 PRMT5 inhibitors, treatment of GBM cells with compound 5 (CMP5) mirrored the effects of PRMT5 knockdown wherein it led to apoptosis of differentiated GBM cells and drove undifferentiated primary patient derived GBM cells into a nonreplicative senescent state.

Conclusion

In vivo antitumor efficacy combined with the specificity of CMP5 underscores the importance of developing it for translation.

Click and release: bioorthogonal approaches to “on-demand” activation of prodrugs

This review summarizes recent developments in using bioorthogonal chemistry in prodrug design for the delivery of traditional small molecule- and gasotransmitter-based therapeutics.

Genetics of metastasis: melanoma and other cancers

Melanoma is a malignant neoplasm of melanocytes that accounts for the majority of skin cancer deaths despite comprising less than 5% of all cutaneous malignancies. Its incidence has increased faster than that of any other cancer over the past half-century and the annual costs of treatment in the United States alone have risen rapidly. Although the majority of primary melanomas are cured with local excision, metastatic melanoma historically carries a grim prognosis, with a median survival of 9 months and a long-term survival rate of 10%. Given the urgent need to develop treatment strategies for metastatic melanoma and the explosion of genetic technologies over the past 20 years, there has been extensive research into the genetic alterations that cause melanocytes to become malignant. More recently, efforts have focused on the genetic changes that drive melanoma metastasis. This review aims to summarize the current knowledge of the genetics of primary cutaneous and ocular melanoma, the genetic changes associated with metastasis in melanoma and other cancer types, and non-genetic factors that may contribute to metastasis.

HPMA Copolymer-Conjugated Pirarubicin in Multimodal Treatment of a Patient with Stage IV Prostate Cancer and Extensive Lung and Bone Metastases

Nanomedicine allows achievement of tumor-selective drug delivery because of the enhanced permeability and retention (EPR) effect of solid tumors. We report here the first clinical application of a new agent-HPMA copolymer-conjugated pirarubicin (P-THP)-with a molecular size of about 8 nm, or 38.5 kDa. A patient had advanced prostate cancer with multiple metastases in the lung, pelvis, femur, and perhaps the sacrum. In April 2013, this 60-year-old patient started treatment with leuprorelin and estradiol, which continued until July 2014, but the patient became refractory to this treatment. So the patient underwent proton beam radiotherapy targeted to the primary prostate cancer, and P-THP was administered for numerous metastatic tumor nodules concomitantly with radiotherapy. This combination therapy had remarkable results, with complete remission of multiple metastases in the lung and bone. The prostate-specific antigen (PSA) value was decreased from about 1000 ng/mL on April 30, 2013, to about 100 ng/mL on June 24, 2013, with hormone therapy, but rose again to 964.2 ng/mL and then to 1472 ng/mL in July 2013, during leuprorelin administration. P-THP treatment administered concomitantly with proton beam irradiation was started in August 2013. The PSA value was decreased to 102 ng/mL on August 26, 2013, and then to 0.971 ng/mL on October 8, 2013, and 0.277 ng/mL on January 15, 2015. The P-THP doses ranged from 30 to 75 mg of free THP equivalent/patient every 2-3 weeks without signs of serious toxicity, such as cardiovascular side effects or a reduction in quality of life. No evidence of relapse was found more than 20 months after P-THP administration. This case demonstrates the value of hydrazone-bonded polymeric drugs in multimodal therapy.

Neoadjuvant Chemotherapy Using Reduced-Dose Docetaxel Followed by Radical Prostatectomy for Patients With Intermediate and High-Risk Prostate Cancer: A Single-Center Study

BACKGROUND

To assess safety, pathologic response rate, and long-term oncologic outcomes of radical prostatectomy (RP) after neoadjuvant chemotherapy using reduced-dose docetaxel without androgen-deprivation therapy in prostate cancer (PCa) patients of intermediate- and high-risk groups.

METHODS

Forty-four patients with PCa (PSA > 10 ng/ml, Gleason score 7 or more, or clinical stage cT2c or more) were included with a median follow-up of 11.4 years after RP. One group (NCT/RP) received neoadjuvant treatment 3-weekly with docetaxel (36 mg/m(2) for up to six cycles, 21 patients), the other (control) group (RP, 23 patients) received RP only.

RESULTS

Toxicities were mild with grade 3 events not exceeding 10%. A statistically significant reduction of PSA > 50% post-chemotherapy was observed in 52.4% cases. Cancer-specific survival (CSS) was 90% in the NCT/RP group and 60.9% in the RP group (P = 0.042). The biochemical recurrence-free survival was 68.5% in the NCT/RP and 37.7% in the RP groups; overall survival was 75.5% and 54.6%, respectively (both P > 0.05).

CONCLUSIONS

The use of neoadjuvant chemotherapy before RP in a selected regimen and dose represents a safe strategy and results in benefits in CSS. Given the limitations of the study, this concept should be evaluated in large, prospective, controlled studies. Prostate 76: 1345-1352, 2016. © 2016 Wiley Periodicals, Inc.

Emodin enhances cisplatin-induced cytotoxicity in human bladder cancer cells through ROS elevation and MRP1 downregulation

Background

Chemoresistance is one of the most leading causes for tumor progression and recurrence of bladder cancer. Reactive oxygen species (ROS) plays a key role in the chemosensitivity of cancer cells. In the present study, emodin (1,3,8-trihydroxy-6-methylanthraquinone) was applied as a ROS generator in combination with cisplatin in T24 and J82 human bladder cancer cells.

Methods

Cell viability and apoptosis rate of different treatment groups were detected by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and flow cytometry (FCM). The expression of transporters was measured at both the transcription and translation levels using PCR and western blotting. In vitro findings were confirmed by in vivo experiments using tumor-bearing mice. The expression of multidrug resistance-associated protein 1 (MRP1) in tumour tissue was measured using immunohistochemistry and side effects of the emodin/cisplatin co-treatment were investigated by histological examination.

Results

Emodin increased the cellular ROS level and effectively enhanced the cisplatin-induced cytotoxicity of T24 and J82 human bladder cancer cells through decreasing glutathione-cisplatin (GSH-cisplatin) conjugates. It blocked the chemoresistance of T24 and J82 cells to cisplatin through suppressing the expression of MRP1. This effect was specific in T24 and J82 cells but not in HCV-29 normal bladder epithelial cells. Consistent with in vitro experiments, emodin/cisplatin co-treatment increased the cell apoptosis and repressed the MRP1 expression in xenograft tumors, and without obvious systemic toxicity.

Conclusions

This study revealed that emodin could increase the cisplatin-induced cytotoxicity against T24 and J82 cells via elevating the cellular ROS level and downregulating MRP1 expression. We suggest that emodin could serve as an effective adjuvant agent for the cisplatin-based chemotherapy of bladder cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2640-3) contains supplementary material, which is available to authorized users.

Systemic therapy in men with metastatic castration-resistant prostate cancer:American Society of Clinical Oncology and Cancer Care Ontario clinical practice guideline

PURPOSE

To provide treatment recommendations for men with metastatic castration-resistant prostate cancer (CRPC).

METHODS

The American Society of Clinical Oncology and Cancer Care Ontario convened an expert panel to develop evidence-based recommendations informed by a systematic review of the literature.

RESULTS

When added to androgen deprivation, therapies demonstrating improved survival, improved quality of life (QOL), and favorable benefit-harm balance include abiraterone acetate/prednisone, enzalutamide, and radium-223 ((223)Ra; for men with predominantly bone metastases). Improved survival and QOL with moderate toxicity risk are associated with docetaxel/prednisone. For asymptomatic/minimally symptomatic men, improved survival with unclear QOL impact and low toxicity are associated with sipuleucel-T. For men who previously received docetaxel, improved survival, unclear QOL impact, and moderate to high toxicity risk are associated with cabazitaxel/prednisone. Modest QOL benefit (without survival benefit) and high toxicity risk are associated with mitoxantrone/prednisone after docetaxel. No benefit and excess toxicity are observed with bevacizumab, estramustine, and sunitinib.

RECOMMENDATIONS

Continue androgen deprivation (pharmaceutical or surgical) indefinitely. Abiraterone acetate/prednisone, enzalutamide, or (223)Ra should be offered; docetaxel/prednisone should also be offered, accompanied by discussion of toxicity risk. Sipuleucel-T may be offered to asymptomatic/minimally symptomatic men. For men who have experienced progression with docetaxel, cabazitaxel may be offered, accompanied by discussion of toxicity risk. Mitoxantrone may be offered, accompanied by discussion of limited clinical benefit and toxicity risk. Ketoconazole or antiandrogens (eg, bicalutamide, flutamide, nilutamide) may be offered, accompanied by discussion of limited known clinical benefit. Bevacizumab, estramustine, and sunitinib should not be offered. There is insufficient evidence to evaluate optimal sequences or combinations of therapies. Palliative care should be offered to all patients.

Carbon monoxide expedites metabolic exhaustion to inhibit tumor growth

One classical feature of cancer cells is their metabolic acquisition of a highly glycolytic phenotype. Carbon monoxide (CO), one of the products of the cytoprotective molecule heme oxygenase-1 (HO-1) in cancer cells, has been implicated in carcinogenesis and therapeutic resistance. However, the functional contributions of CO and HO-1 to these processes are poorly defined. In human prostate cancers, we found that HO-1 was nuclear localized in malignant cells, with low enzymatic activity in moderately differentiated tumors correlating with relatively worse clinical outcomes. Exposure to CO sensitized prostate cancer cells but not normal cells to chemotherapy, with growth arrest and apoptosis induced in vivo in part through mitotic catastrophe. CO targeted mitochondria activity in cancer cells as evidenced by higher oxygen consumption, free radical generation, and mitochondrial collapse. Collectively, our findings indicated that CO transiently induces an anti-Warburg effect by rapidly fueling cancer cell bioenergetics, ultimately resulting in metabolic exhaustion.

Systemic therapy in men with metastatic castration-resistant prostate cancer: a systematic review

AIMS

Since 2004, docetaxel-based chemotherapy has been the standard of care for men with metastatic castration-resistant prostate cancer (mCRPC), but recently randomised controlled trials (RCTs) of novel agents have shown promise in extending overall survival. These trials have evaluated agents delivered before chemotherapy, to replace or supplement docetaxel, or addressed treatment options for men who have progressed on docetaxel therapy. This review was undertaken to determine which systemic therapies improve cancer- or patient-related outcomes in men with mCRPC.

MATERIALS AND METHODS

Searches were carried out in MEDLINE, EMBASE, the Cochrane Library and relevant conference proceedings. Eligible articles included RCTs comparing systemic therapy or combination (excluding primary or secondary androgen deprivation therapy, bone protective agents or radionuclides) with placebo or other agents in men with mCRPC.

RESULTS

Twenty-five RCTs met the selection criteria. In chemotherapy-naive patients, targeted therapy with tasquinimod conferred a benefit in progression-free survival. Immunotherapy with sipuleucel-T extended overall survival and was well tolerated, but had no effect on the time to disease progression. Hypercastration with abiraterone extended progression-free survival, whereas overall survival was improved but not statistically proven. In the chemotherapy setting, updated and new trials of docetaxel alone confirmed the survival benefit seen in previous studies. A survival benefit with the addition of estramustine to docetaxel shown in a previous study did not lead to an improvement in pain palliation or quality of life. Trials of combining targeted therapies with docetaxel generally did not extend survival. The addition of bevacizumab improved progression-free survival, but not overall survival. The addition of GVAX immunotherapy or calcitriol was harmful. In the post-chemotherapy setting, progression-free and overall survival benefits were detected with cabazitaxel, abiraterone and enzalutamide. Cabazitaxel was associated with greater toxicity, whereas abiraterone and enzalutamide had less severe adverse effects. Satraplatin and sunitinib both extended progression-free survival, but did not improve overall survival.

CONCLUSION

Docetaxel-based chemotherapy remains the standard of care in men with mCRPC who are candidates for palliative systemic therapy. Promising results are emerging with sipuleucel-T and abiraterone in the pre-docetaxel setting and cabazitaxel, abiraterone and enzalutamide in patients who progress on or after docetaxel. Further research to determine the optimal choice, sequence or even the combination of these agents is necessary.

Juglone, isolated from Juglans mandshurica Maxim, induces apoptosis via down-regulation of AR expression in human prostate cancer LNCaP cells

Juglone is a natural compound which has been isolated from Juglans mandshurica Maxim. Recent studies have shown that juglone had various pharmacological effects such as anti-viral, anti-bacterial and anti-cancer. However, its anti-cancer activity on human prostate cancer LNCaP cell has not been examined. Thus, the current study was designed to elucidate the molecular mechanism of apoptosis induced by juglone in androgen-sensitive prostate cancer LNCaP cells. MTT assay was performed to examine the anti-proliferative effect of juglone. Occurrence of apoptosis was detected by Hoechst 33342 staining and flow cytometry in LNCaP cells treated with juglone for 24h. The result shown that juglone inhibited the growth of LNCaP cells in a dose-dependent manner. Morphological changes of apoptotic body formation after juglone treatment were observed by Hoechst 33342 staining. This apoptotic induction was associated with loss of mitochondrial membrane potential, and caspase-3, -9 activation. Moreover, we found that juglone significantly inhibited the expression levels of androgen receptor (AR) and prostate-specific antigen (PSA) in a dose-dependent manner, as well as abrogated up-regulation of AR and PSA genes with and/or without dihydrotestosterone (DHT). Take together, our results demonstrated that juglone might induce the apoptosis in LNCaP cell via down-regulation of AR expression. Therefore, our results indicated that juglone may be a potential candidate of drug for androgen-sensitive prostate cancer.

Development of animal models underlining mechanistic connections between prostate inflammation and cancer

The characterization of animal models has indicated that the genetic, dietary and environmental factors and hormonal imbalance may influence the risk to develop prostate inflammatory lesions and prostate cancer (PC) confirming human epidemiologic data. It is now established that the prostate inflammatory response typically results in major changes in the local microenvironment of epithelial cells of the prostate gland, including an intense stromal remodeling, activation of fibroblasts, infiltration of immune cells such as mast cells, macrophages and B and T lymphocytes and collagen deposition. The immune cells recruited at prostate inflammatory lesions and myofibroblasts may contribute to the release of numerous pro-inflammatory cytokines and chemokines that in turn can promote the oxidative stress, genomic instability and proliferation of epithelial cells. The accumulation of additional genetic and/or epigenetic alterations in prostatic stem/progenitor cells may subsequently culminate to their malignant transformation and PC initiation and progression and more particularly with advancing age. The potential mechanistic relationships between the molecular events associated with the persistent inflammatory response and prostate carcinogenesis have important implications for optimizing the current therapies against different prostatic disorders and PCs.

Second-line therapy for castrate-resistant prostate cancer: a literature review

Despite a survival benefit in the first-line treatment of castrate-resistant prostate cancer (CRPC) with docetaxel, the prognosis remains limited. There are increasing options available for patients with CRPC in the second-line setting, but there is currently little consensus regarding the optimal treatment. There have been numerous phase II and retrospective studies examining second-line options in CRPC, including retreatment with docetaxel, mitoxantrone, cyclophosphamide and carboplatin, which can be associated with meaningful responses in a significant minority of patients. In 2010 three randomized trials were published or presented which demonstrated a survival benefit in the second-line setting. These included cabazitaxel compared with mitoxantrone, sipuleucel-T (immunotherapy) and abiraterone acetate versus placebo. Ongoing research in the second-line setting of CRPC to optimize treatment options, with the objectives of survival prolongation, improvement in quality of life and pain management, is still needed.

Ten years of docetaxel-based therapies in prostate adenocarcinoma: a systematic review and meta-analysis of 2244 patients in 12 randomized clinical trials

BACKGROUND

Chemotherapy can reduce serum prostate-specific antigen (PSA) levels and relieve pain in some patients with castration-resistant prostate cancer (CRPC). To improve therapeutic efficacy numerous randomized trials have investigated docetaxel-based combination regimens. The present analysis tries to overcome the statistical limitations of the individual trials and investigates the treatment effects in total and in various combination groups.

METHODS

The Medline, Embase, Cancerlit, and American Society of Clinical Oncology Abstract databases were searched for published randomized placebo-controlled trials evaluating the use of docetaxel-based regimens in patients with CRPC. The outcomes assessed were overall survival, overall response rate, PSA response rate, and adverse effects.

RESULTS

Twelve articles (2244 participants) were included in the meta-analysis. The analysis demonstrates a higher PSA response rate from docetaxel-based combinations when compared with docetaxel alone (relative risk [RR] = 1.16; P = .010). The estimated median survival in docetaxel-based combinations was statistically significantly longer than in the docetaxel-alone group (22.0 vs. 18.4 months; P = .037). Grade 3 or 4 neutropenia as well as grade 3 or 4 thromboembolic events were similar in both arms (overall RR, 0.87 [confidence interval (CI) 0.71-1.07]; P = .20 and overall RR 1.52 [0.79 - 2.90]; P = .21, respectively).

CONCLUSION

The analysis of 12 randomized trials provides evidence in favor of docetaxel-based combination chemotherapy for patients with CRPC and good performance status.

Current management of castrate-resistant prostate cancer

Prostate cancer (PCa) is the most frequently diagnosed cancer in North America. Castrate-resistant PCa presents a spectrum of disease ranging from rising PSA levels in the absence of metastases or symptoms and despite androgen-deprivation therapy, to metastases and significant debilitation from cancer symptoms. Castrate-resistant PCa is usually suspected in patients with new symptoms on androgen deprivation therapy, with a rising PSA, or with new evidence of disease on bone scans or computed tomography scans. Institution of treatment and the choice of systemic or local therapy depend on a number of factors. This review discusses the various currently available treatments for patients with castrate-resistant PCa, from secondary hormonal manipulations to options for post-docetaxel systemic therapy.

Frequent gene products and molecular pathways altered in prostate cancer- and metastasis-initiating cells and their progenies and novel promising multitargeted therapies

Recent gene expression profiling analyses and gain- and loss-of-function studies performed with distinct prostate cancer (PC) cell models indicated that the alterations in specific gene products and molecular pathways often occur in PC stem/progenitor cells and their progenies during prostate carcinogenesis and metastases at distant sites, including bones. Particularly, the sustained activation of epidermal growth factor receptor (EGFR), hedgehog, Wnt/β-catenin, Notch, hyaluronan (HA)/CD44 and stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) during the epithelial-mesenchymal transition (EMT) process may provide critical functions for PC progression to locally invasive, metastatic and androgen-independent disease states and treatment resistance. Moreover, an enhanced glycolytic metabolism in PC stem/progenitor cells and their progenies concomitant with the changes in their local microenvironment, including the induction of tumor hypoxia and release of diverse soluble factors by tumor myofibroblasts, also may promote the tumor growth, angiogenesis and metastases. More particularly, these molecular transforming events may cooperate to upregulate Akt, nuclear factor (NF)-κB, hypoxia-inducible factors (HIFs) and stemness gene products such as Oct3/4, Sox2, Nanog and Bmi-1 in PC cells that contribute to their acquisition of high self-renewal, tumorigenic and invasive capacities and survival advantages during PC progression. Consequently, the molecular targeting of these deregulated gene products in the PC- and metastasis-initiating cells and their progenies represent new promising therapeutic strategies of great clinical interest for eradicating the total PC cell mass and improving current antihormonal treatments and docetaxel-based chemotherapies, thereby preventing disease relapse and the death of PC patients.

Randomized trial of the effect of the low molecular weight heparin nadroparin on survival in patients with cancer

PURPOSE

Earlier studies showed that low molecular weight heparin significantly prolongs the survival of a wide variety of patients with cancer without venous thromboembolism. This study was designed to confirm these findings in a more homogeneous group of patients with cancer.

PATIENTS AND METHODS

In this multicenter, randomized, open-label study, patients with non-small-cell lung cancer (stage IIIB), hormone-refractory prostate cancer, or locally advanced pancreatic cancer were randomly assigned to nadroparin or to no nadroparin in addition to their standard anticancer treatment. In the nadroparin arm, subcutaneous nadroparin was administered for 6 weeks (2 weeks at therapeutic dose, and 4 weeks at half therapeutic dose). The patients were eligible to receive additional cycles of nadroparin (2 weeks at therapeutic dose, and 4 weeks of washout period). Outcomes were overall survival, time to progression, and major bleeding. All study outcomes were adjudicated by an independent, blinded committee.

RESULTS

A total of 244 patients were allocated to nadroparin, and 259 were allocated to the control group. A median survival of 13.1 months was observed in the nadroparin recipients compared with 11.9 months in the no-treatment arm (hazard ratio, 0.94; 95% CI, 0.75 to 1.18, adjusted for cancer type). No difference in time to progression was observed. The number of major bleedings was comparable at 4.1% in the nadroparin set and 3.5% in the control set.

CONCLUSION

This study did not show a survival benefit of nadroparin in patients with advanced prostate, lung, or pancreatic cancer. Given the ongoing studies in this area and the previous data, the role of low molecular weight heparins in cancer survival remains undefined.

Animal models relevant to human prostate carcinogenesis underlining the critical implication of prostatic stem/progenitor cells

Recent development of animal models relevant to human prostate cancer (PC) etiopathogenesis has provided important information on the specific functions provided by key gene products altered during disease initiation and progression to locally invasive, metastatic and hormone-refractory stages. Especially, the characterization of transgenic mouse models has indicated that the inactivation of distinct tumor suppressor proteins such as phosphatase tensin homolog deleted on chromosome 10 (PTEN), Nkx3.1, p27(KIP1), p53 and retinoblastoma (pRb) may cooperate for the malignant transformation of prostatic stem/progenitor cells into PC stem/progenitor cells and tumor development and metastases. Moreover, the sustained activation of diverse oncogenic signaling elements, including epidermal growth factor receptor (EGFR), sonic hedgehog, Wnt/β-catenin, c-Myc, Akt and nuclear factor-kappaB (NF-κB) also may contribute to the acquisition of more aggressive and hormone-refractory phenotypes by PC stem/progenitor cells and their progenies during disease progression. Importantly, it has also been shown that an enrichment of PC stem/progenitor cells expressing stem cell-like markers may occur after androgen deprivation therapy and docetaxel treatment in the transgenic mouse models of PC suggesting the critical implication of these immature PC cells in treatment resistance, tumor re-growth and disease recurrence. Of clinical interest, the molecular targeting of distinct gene products altered in PC cells by using different dietary compounds has also been shown to counteract PC initiation and progression in animal models supporting their potential use as chemopreventive or chemotherapeutic agents for eradicating the total tumor cell mass, improving current anti-hormonal and chemotherapies and preventing disease relapse.

Salvage chemotherapy for hormone-refractory prostate cancer: Association of Adriamycin and ifosfamide

Prostate carcinoma is the most common cancer in men. Hormone-resistance is the natural history of this metastatic disease and requires the use of docetaxel as the standard chemotherapy. At present, there is no approved second-line treatment. Here, we report a combination of treatment with Adriamycin and ifosfamide in a series of 7 relatively young patients with an average age of 57 years at the time of diagnosis. Chemotherapy was administered over 3 days with the following schedule: 20 mg/m(2) Adriamycin per day and 1-1.5 mg/m(2) ifosfamide per day, in association with Uromitexan. Treatment was repeated every 3 weeks. Three biological responses, one CT scan response, one bone scan response and two CT scan stabilizations, were obtained. Mean survival following this combination was 6.6 months, and over 26 months after first-line chemotherapy. Tolerance was good with the use of granulocyte-colony stimulating factors. Our observations clearly show that the use of this type of salvage therapy for relatively young patients in good physical condition should be further assessed in a clinical trial, particularly when different lines of chemotherapy are required.

Therapy-induced senescence in cancer

Cellular senescence is a response to nonlethal stress that results in persistent cytostasis with a distinct morphological and biochemical phenotype. The senescence phenotype, detected in tumors through the expression of mRNA and protein markers, can be generated in cancer cells lacking functional p53 and retinoblastoma protein. Current research suggests that therapy-induced senescence (TIS) represents a novel functional target that may improve cancer therapy. TIS can be induced in immortal and transformed cancer cells by selected anticancer compounds or radiation, and accumulating data indicate that TIS may produce reduced toxicity-related side effects and increased tumor-specific immune activity. This review examines the current status of TIS-regulated mechanisms, agents, and senescence biomarkers with the goal of encouraging further development of this approach to cancer therapy. Remaining hurdles include the lack of efficient senescence-inducing agents and incomplete biological data on tumor response. The identification of additional compounds and other targeted approaches to senescence induction will further the development of TIS in the clinical treatment of cancer.

Constructing a conceptual framework of patient-reported outcomes for metastatic hormone-refractory prostate cancer

OBJECTIVE

A conceptual framework for patient-reported outcomes (PROs) is a structured representation of outcome concepts and issues. Our aim was to develop a conceptual framework of PROs for hormone-refractory prostate cancer (HRPC) to support measurement clarity.

METHODS

Relevant outcome issues were identified from review of recent clinical trials. This provided content for an interview with 15 metastatic HRPC patients and a survey of 10 practitioners. All participants were asked about the relevance and importance of 26 outcomes and were allowed to nominate new outcomes. Practitioners were also asked to determine which outcomes endorsed by patients were attributable to the disease (symptoms) versus treatment (side effects). Analyses of archived clinical trial data were used to verify and augment the interview and survey results.

RESULTS

Patients endorsed 11 concerns as relevant and important to HRPC including general pain, bone pain, urinary problems, fatigue, appetite loss, constipation, erectile dysfunction, peripheral neuropathy, diarrhea, PSA anxiety, and changes in self image. Practitioner judgments helped classify each concern into one of four categories, disease symptom, treatment side effect, both symptom and side effect, or psychological concern. Additionally, patients endorsed (and practitioners confirmed) the relevance and importance of several general domains of quality of life. Analyses of archived data confirmed the importance of these issues and suggested two additional concerns.

CONCLUSION

Findings were used to propose a conceptual framework of PROs for metastatic HRPC. Such frameworks can be used to help specify targets for assessment in clinical studies such as treatment trials.

Novel therapies against aggressive and recurrent epithelial cancers by molecular targeting tumor- and metastasis-initiating cells and their progenies

A growing body of experimental evidence has revealed that the highly tumorigenic cancer stem/progenitor cells endowed with stem cell-like properties might be responsible for initiation and progression of numerous aggressive epithelial cancers into locally invasive, metastatic and incurable disease states. The malignant transformation of tissue-resident adult stem/progenitor cells or their progenies into tumorigenic and migrating cancer stem/progenitor cells and their resistance to current cancer therapies have been associated with their high expression levels of specific oncogenic products and drug resistance-associated molecules. In this regard, we describe the tumorigenic cascades that are frequently activated in cancer stem/progenitor cells versus their differentiated progenies during the early and late stages of the epithelial cancer progression. The emphasis is on the growth factor signaling pathways involved in the malignant behavior of prostate and pancreatic cancer stem/progenitor cells and their progenies. Of clinical interest, the potential molecular therapeutic targets to eradicate the tumor- and metastasis-initiating cells and their progenies and develop new effective combination therapies against locally advanced and metastatic epithelial cancers are also described.

Metronomic chemotherapy: principles and lessons learned from applications in the treatment of metastatic prostate cancer

By frequent and protracted administration of conventional cytotoxic drugs without prolonged interruptions, the primary treatment target shifts from the tumor cell population to the tumor vasculature. This "metronomic" way of chemotherapy administration results in antivascular effects, the mechanistic basis of which remains to be fully elucidated. We outline the basic aspects of the metronomic concept, describe the results of clinical applications of such chemotherapy by focusing on studies in metastatic prostate cancer, and discuss certain shortcomings. Based on preclinical findings, we finally point to the possible ways to address these shortcomings in order to bring this novel and promising use of conventional anticancer agents to full fruition.

Pilot study of rapamycin in patients with hormone-refractory prostate cancer

BACKGROUND

Currently, no second-line treatment exists for hormonerefractory prostate cancer (HRPC) cases that fail docetaxel regimens. Rapamycin, an immunosuppressive macrolide, inhibits metastatic prostate tumor growth and angiogenesis in in vivo mouse models. This pilot study assessed the antitumor activity, safety, and toxicity of rapamycin in patients with HRPC.

PATIENTS AND METHODS

Eligible patients had HRPC and disease progression. The initial dose of rapamycin was 0.15 mg/kg followed by 0.04 mg/kg daily without interruption. Rapamycin levels were measured every 28 days with dose adjustments of 0.04-0.06 mg/kg as necessary to maintain levels between 6-10 ng/mL. Patients were evaluated every 4 weeks for prostate-specific antigen (PSA) and safety and every 8 weeks for radiographic response.

RESULTS

Thirteen patients were enrolled from January 2005 to February 2006. One was not evaluable for response. Responses were seen in 2 of 12 evaluable patients (17%). One patient experienced a 50% decrease in absolute PSA and partial radiographic response; another experienced a PSA response only. Four patients had stable disease (33%). The median progression-free survival was 4.2 months (range, 1.9-23.3 months), and overall survival was 23.3+ months (range, 1.9-34.3+ months). Diarrhea (69%), fatigue (46%), and nausea (46%) were the most common adverse events. Rapamycin was well tolerated and showed signs of antitumor activity.

CONCLUSION

Rapamycin and other inhibitors of mammalian targets of rapamycin warrant further study in developing combination therapies with chemotherapy or radiation.

Functions of normal and malignant prostatic stem/progenitor cells in tissue regeneration and cancer progression and novel targeting therapies

This review summarizes the recent advancements that have improved our understanding of the functions of prostatic stem/progenitor cells in maintaining homeostasis of the prostate gland. We also describe the oncogenic events that may contribute to their malignant transformation into prostatic cancer stem/progenitor cells during cancer initiation and progression to metastatic disease stages. The molecular mechanisms that may contribute to the intrinsic or the acquisition of a resistant phenotype by the prostatic cancer stem/progenitor cells and their differentiated progenies with a luminal phenotype to the current therapies and disease relapse are also reviewed. The emphasis is on the critical functions of distinct tumorigenic signaling cascades induced through the epidermal growth factor system, hedgehog, Wnt/beta-catenin, and/or stromal cell-derived factor-1/CXC chemokine receptor-4 pathways as well as the deregulated apoptotic signaling elements and ATP-binding cassette multidrug transporter. Of particular therapeutic interest, we also discuss the potential beneficial effects associated with the targeting of these signaling elements to overcome the resistance to current treatments and prostate cancer recurrence. The combined targeted strategies toward distinct oncogenic signaling cascades in prostatic cancer stem/progenitor cells and their progenies as well as their local microenvironment, which could improve the efficacy of current clinical chemotherapeutic treatments against incurable, androgen-independent, and metastatic prostate cancers, are also described.

Improvement of cytotoxic effects induced by mitoxantrone on hormone-refractory metastatic prostate cancer cells by co-targeting epidermal growth factor receptor and hedgehog signaling cascades

The results of the present study revealed for the first time the possibility to use a combination of mitoxantrone with gefitinib and cyclopamine for inhibiting the growth of epidermal growth factor (EGF), sonic hedgehog- (SHHNp), and serum-stimulated androgen-sensitive LNCaP-C33 and androgen-independent (AI) LNCaP-C81, DU145 and PC3 prostate cancer (PC) cells. The supra-additive anti-proliferative effects of drugs were mediated via a blockade of the PC3 cells in the G(1) and G(2)M phases of the cell cycle. Importantly, the combination of mitoxantrone plus gefitinib and/or cyclopamine also caused a higher rate of apoptotic death of PC cells including enriched fraction of CD44(high) PC3 cell subpopulation as compared to the individual agents or bi-combination of drugs. The cytotoxic effects induced by mitoxantrone, gefitinib and cyclopamine on PC3 cells appear to be at least partly mediated through the depolarization of the mitochondrial membrane, release of cytochrome c into the cytosol, hydrogen peroxide production and activation of caspase cascades. These findings indicate that the simultaneous blockade of EGF-EGFR and sonic hedgehog tumorigenic signaling cascades may represent a promising strategy for improving the efficacy of current mitoxantrone-based therapies against incurable AI and metastatic PCs in the clinics.

American Society of Clinical Oncology Endorsement of the Cancer Care Ontario Practice Guideline on Nonhormonal Therapy for Men With Metastatic Hormone-Refractory (castration-resistant) Prostate Cancer

Purpose

In 2006, the American Society of Clinical Oncology (ASCO) Board of Directors (BOD) approved a policy and a set of procedures for endorsing clinical practice guidelines that have been developed by other professional organizations.

Methods

The Cancer Care Ontario (CCO) Guideline on Non-Hormonal Therapy for Men With Metastatic Hormone-Refractory Prostate Cancer (HRPC) was reviewed for developmental rigor by methodologists. An ad hoc prostate cancer guideline review panel consisting of prostate cancer experts reviewed the content.

Results

The ASCO ad hoc prostate cancer guideline review panel concurred that the recommendations are clear, thorough, based on the most relevant scientific evidence in this content area, and present options that will be acceptable to patients. The CCO guideline was subsequently endorsed by the ASCO BOD. The guideline recommends the use of docetaxel, prednisone/hydrocortisone, and/or mitoxantrone in specific settings. Docetaxel-based chemotherapy is the only treatment that has demonstrated an overall survival benefit in men with HRPC. The use of estramustine in combination with other cytotoxic agents is not recommended. Continued gonadal androgen suppression and discontinuance of antiandrogens is recommended for men receiving chemotherapy.

Conclusion

The review panel agreed with the recommendations as stated in the CCO guideline, with the following qualifications: two of the ASCO content reviewers noted the importance of considering other, nonhormonal therapies in this context that are beyond the scope of this guideline. The review panel notes that CCO has published separate guidelines on radiopharmaceuticals and bisphosphonates in men with castration-resistant (ie, hormone-refractory) metastatic prostate cancer.

Combined targeting of epidermal growth factor receptor and hedgehog signaling by gefitinib and cyclopamine cooperatively improves the cytotoxic effects of docetaxel on metastatic prostate cancer cells

The epidermal growth factor receptor (EGFR) and hedgehog cascades provide a critical role in prostate cancer progression and contribute to the resistance to clinical therapies and disease relapse. Therefore, we evaluated, for the first time, the antiproliferative and cytotoxic effects induced by a combination of selective inhibitors of EGFR tyrosine kinase and smoothened hedgehog signaling element, gefitinib and cyclopamine, with a current chemotherapeutic drug used in the clinics, docetaxel, on some metastatic prostate cancer cell lines. Immunohistochemical analyses revealed that sonic hedgehog (SHH) expression was enhanced in 39% of primary prostatic adenocarcinomas (Gleason scores 4-10) compared with the corresponding normal tissues of the same prostate gland from 32 prostate cancer patients. The confocal microscopy and Western blot analyses have also indicated the high expression levels of SHH and EGFR in metastatic LNCaP, DU145, and PC3 cells. Moreover, the results revealed that the drugs, alone or in combination, at lower concentrations inhibited the growth of EGF plus SHH-stimulated and serum-stimulated androgen-responsive LNCaP-C33 and androgen-independent LNCaP-C81, DU145, and PC3 cells. Importantly, the combined docetaxel, gefitinib, and cyclopamine also caused a higher rate of apoptotic death of prostate cancer cells compared with individual agents. The cytotoxic effects induced by these drugs in PC3 cells seem to be mediated in part through the cellular ceramide production and activation of caspase cascades via a mitochondrial pathway and the release of cytochrome c into the cytosol. Additionally, the combined agents were more effective at suppressing the invasiveness of PC3 cells through Matrigel in vitro than the single drugs. These findings indicate that the combined use of inhibitors of EGF-EGFR and hedgehog signaling with docetaxel could represent a more promising strategy for treatment in patients with metastatic and androgen-independent prostate cancer.