A randomized phase II trial of the matrix metalloproteinase inhibitor BMS-275291 in hormone-refractory prostate cancer patients with bone metastases

Markers of bone metabolism and overall survival in men with bone-metastatic hormone sensitive prostate cancer (HSPC): A subset analysis of SWOG S1216, a phase III trial of androgen deprivation with or without orteronel

BACKGROUND

Circulating biomarkers of bone metabolism are significantly associated with overall survival (OS) in men with advanced prostate cancer. In the SWOG S1216 phase III trial, we showed that elevated bone biomarkers are significantly associated with an increased risk of death in hormone-sensitive prostate cancer (HSPC) regardless of the status of bone metastases, identifying three risk groups with differential OS outcomes based on bone biomarker status. Here we report the association of bone biomarkers with OS in men with HSPC and documented skeletal metastases as part of a planned subset analysis of S1216.

METHODS

Bone resorption [C-telopeptide (CTx); Pyridinoline (PYD)] and bone formation markers [C-terminal collagen propeptide (CICP); bone alkaline phosphatase (BAP)] were assessed in blood from men with bone metastatic HSPC. Patients were randomly divided into training (n = 238) and validation (n = 475) sets. In the training set, recursive partitioning that maximizes discrimination of OS was used to identify the dichotomous cut-point for each biomarker and for a combination of biomarker split points to define prognostic groups. In the validation set, Cox proportional hazards models were used to assess the impact of biomarkers on OS, adjusted for patient and tumor characteristics.

RESULTS

Of 1279 men, 713 had both baseline bone metastases and evaluable bone biomarkers. Patient characteristics were similar between the overall population and the subset with bone metastases. Elevated levels of CICP, CTX, and PYD were strongly prognostic for OS. Hazard ratios (95% CI) for OS adjusted for treatment arm and baseline clinical variables were: BAP-1.31 (0.93, 1.84), p = 0.12; CICP-1.58 (1.09, 2.29), p < 0.02; CTx - 1.55 (1.12, 2.15), p = 0.008; and PYD-1.66 (1.27, 2.217), p = 0.0002. There was no evidence of interaction between elevated biomarkers and treatment (all p > 0.2). Recursive partitioning algorithms identified four groups of patients with differential OS outcomes based on bone biomarkers, adjusted for baseline clinical variables, with median OS ranging from 2.3 years (highest risk group) to 7.5 years (lowest risk group).

CONCLUSIONS

In this planned S1216 subset analysis of men with HSPC and bone metastases, elevated serum markers of bone metabolism were significantly associated with worse OS. Bone biomarker levels alone and in combination with patient and tumor characteristics identify unique subsets of men with differential OS outcomes.

CLINICALTRIALS

GOV IDENTIFIER

NCT01809691.

Bone Biomarkers and Subsequent Survival in Men with Hormone-sensitive Prostate Cancer: Results from the SWOG S1216 Phase 3 Trial of Androgen Deprivation Therapy with or Without Orteronel

BACKGROUND

Bone biomarkers are strongly prognostic for overall survival (OS) in men with castration-resistant prostate cancer but not fully established for hormone-sensitive prostate cancer (HSPC).

OBJECTIVE

Bone biomarkers in HSPC were prospectively evaluated as part of a phase 3 study of androgen deprivation therapy ± the CYP17 inhibitor orteronel.

DESIGN, SETTING, AND PARTICIPANTS

Patients were randomly divided into training (n = 316) and validation (n = 633) sets. Recursive partitioning and Cox proportional hazard models were employed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Bone resorption (C-telopeptide and pyridinoline) and bone formation markers (C-terminal collagen propeptide and bone alkaline phosphatase) were assessed from patient sera.

RESULTS AND LIMITATIONS

Of 1279 men, 949 had evaluable baseline bone biomarkers. Optimal cutoffs were identified to define elevated levels of each of the four biomarkers (all p < 0.05) that were associated with worse OS. After adjusting for clinical risk factors in the validation set, elevated bone biomarkers were statistically significantly associated with an increased risk of death (hazard ratios ranging from 1.37 to 1.92). Recursive partitioning algorithms applied to the training set identified three risk groups (low, intermediate, and poor) with differential OS outcomes (median OS: 8.2, 5.1, and 2.1 yr, respectively) based on combinations of bone biomarkers. These results were confirmed in the validation set.

CONCLUSIONS

In men with HSPC initiating androgen deprivation therapy, bone biomarkers are strongly and independently prognostic for OS. Bone biomarker levels alone or in combination with clinical covariates identify unique subsets of men with differential OS outcomes. These results validate the clinical value of bone biomarker assessment in the HSPC state, extending bone biomarker utility beyond the castration-resistant state.

PATIENT SUMMARY

In men with newly diagnosed metastatic prostate cancer, high levels of bone turnover biomarkers are associated with a shorter lifespan.

Proteases Regulate Cancer Stem Cell Properties and Remodel Their Microenvironment

Proteolytic activity is perturbed in tumors and their microenvironment, and proteases also affect cancer stem cells (CSCs). CSCs are the therapy-resistant subpopulation of cancer cells with tumor-initiating capacity that reside in specialized tumor microenvironment niches. In this review, we briefly summarize the significance of proteases in regulating CSC activities with a focus on brain tumor glioblastoma. A plethora of proteases and their inhibitors participate in CSC invasiveness and affect intercellular interactions, enhancing CSC immune, irradiation, and chemotherapy resilience. Apart from their role in degrading the extracellular matrix enabling CSC migration in and out of their niches, we review the ability of proteases to modulate CSC properties, which prevents their elimination. When designing protease-oriented therapies, the multifaceted roles of proteases should be thoroughly investigated.

Outline of gelatinase inhibitors as anti-cancer agents: A patent mini-review for 2010-present

Matrix metalloproteinases (MMPs) are involved in several pathological and physiological functions. Gelatinases (MMP-2 and -9) have significant attention as therapeutic targets against cancer. Gelatinase inhibitors have demonstrated their effectiveness in several diseases including cancer. However, it is quite a challenging task to develop inhibitors as a therapeutic agent. This review summarizes the patent dedicated to the medicinal chemistry of gelatinase inhibitor reported over last decades. We examine the patent being pursued for gelatinase inhibitor development to highlight the key issues. The main aim is to provide the scientific community with an overview of the patented gelatinase inhibitors to allow further development. During early 2000s, some MMP inhibitors failed to pass the clinical trials. Hence, the lessons learned from early evidence and recent knowledge in that field will rejuvenate the development of selective inhibitors. Various studies and patents have continued in the recent years to expand knowledge. Continuously, our research team has been involved in the design of potent and selective gelatinase inhibitors for the past few years. This study is a part of our efforts. This study may be beneficial in the design and development of better gelatinase inhibitors in the future.

Silencing miR-202-3p increases MMP-1 and promotes a brain invasive phenotype in metastatic breast cancer cells

BACKGROUND

Brain metastasis (BM) is a major cause of morbidity and mortality in breast cancer (BC) and its molecular mechanism remains poorly understood. Transmigration of metastatic cells through the brain endothelium is an essential step in BM. Metalloproteinase-1 (MMP-1) overexpression plays a key role in promoting trans-endothelial migration by degrading the inter-endothelial junctions and disrupting the endothelial integrity. However, little is known about the molecular mechanisms that induce MMP-1 in metastatic cells granting them a brain invasive phenotype. MiR-202-3p is downregulated in brain metastases compared to primary breast tumors and directly targets MMP-1. Here, we unraveled a critical role of miR-202-3p loss in MMP-1 upregulation promoting transmigration of metastatic cells through the brain endothelium.

METHODS

A variant of the MDA-MB-231 human BC cell line (MDA-MB-231-BrM2) selected for its propensity to form brain metastases was found to express high levels of MMP-1 and low levels of miR-202-3p compared to the parental cells. Using a gain-and-loss of function approach, we modulated levels of miR-202-3p and examined the resultant effect on MMP-1 expression. Effect of miR-202-3p modulation on integrity of the brain endothelium and the transmigrative ability of BC cells were also examined.

RESULTS

Loss of miR-202-3p in breast cancer cells enhanced their transmigration through the brain endothelium by upregulating MMP-1 and disrupting the inter-endothelial junctions (claudin-5, ZO-1 and ß-catenin). Restoring miR-202-3p exerted a metastasis-suppressive effect and preserved the endothelial barrier integrity.

CONCLUSIONS

Our study identified a critical regulatory role of miR-202-3p in brain metastasis and shed light on miR-202-3p/MMP-1 axis as a novel prognostic and therapeutic target that can be exploited to predict and prevent brain metastasis in breast cancer patients.

Biomarkers and Bone Imaging Dynamics Associated with Clinical Outcomes of Oral Cabozantinib Therapy in Metastatic Castrate-Resistant Prostate Cancer

PURPOSE

Cabozantinib is a multitargeted tyrosine kinase inhibitor that demonstrated remarkable responses on bone scan in metastatic prostate cancer. Randomized trials failed to demonstrate statistically significant overall survival (OS). We studied the dynamics of biomarker changes with imaging and biopsies pretherapy and posttherapy to explore factors that are likely to be predictive of efficacy with cabozantinib.Experimental Design: Eligibility included patients with metastatic castrate-resistant prostate cancer with normal organ function and performance status 0-2. Cabozantinib 60 mg orally was administered daily. Pretherapy and 2 weeks post, ^99mTc-labeled bone scans, positron emission tomography with ¹⁸F-sodium fluoride (NaF-PET) and ¹⁸F-(1-(2'-deoxy-2'-fluoro-β-D-arabinofuranosyl) thymine (FMAU PET) scans were conducted. Pretherapy and posttherapy tumor biopsies were conducted, and serum and urine bone markers were measured.

RESULTS

Twenty evaluable patients were treated. Eight patients had a PSA decline, of which 2 had a decline of ≥50%. Median progression-free survival (PFS) and OS were 4.1 and 11.2 months, respectively, and 3 patients were on therapy for 8, 10, and 13 months. The NaF-PET demonstrated a median decline in SUVmax of -56% (range, -85 to -5%, n = 11) and -41% (range, -60 to -25%, n = 9) for patients who were clinically stable and remained on therapy for ≥4 or <4 cycles, respectively. The FMAU PET demonstrated a median decline in SUVmax of -44% (-60 to -14%) and -42% (-63% to -23%) for these groups. The changes in bone markers and mesenchymal epithelial transition/MET testing did not correlate with clinical benefit.

CONCLUSIONS

Early changes in imaging and tissue or serum/urine biomarkers did not demonstrate utility in predicting clinical benefit with cabozantinib therapy.

Wnt signaling in bone metastasis: mechanisms and therapeutic opportunities

Bone metastasis frequently occurs in advanced cancer patients, who will develop osteogenic/osteolytic bone lesions in the late stage of the disease. Wnt signaling pathway, which is mainly grouped into the β-catenin dependent pathway and β-catenin independent pathway, is a well-organized cascade that has been reported to play important roles in a variety of physiological and pathological conditions, including bone metastasis. Regulation of Wnt signaling in bone metastasis involves multiple stages, including dissemination of primary tumor cells to bone, dormancy and outgrowth of metastatic tumor cells, and tumor-induced osteogenic and osteolytic bone destruction, suggesting the importance of Wnt signaling in bone metastasis pathology. In this review, we will introduce the involvement of Wnt signaling components in specific bone metastasis stages and summarize the promising Wnt modulators that have shown potential as bone metastasis therapeutics, in the hope to maximize the therapeutic opportunities of Wnt signaling for bone metastasis.

Matrix Metalloproteinase Inhibitors in Cancer Therapy: Turning Past Failures Into Future Successes

The matrix metalloproteinases (MMP) are a family of proteolytic enzymes that degrade multiple components of the extracellular matrix. A large body of experimental and clinical evidence has implicated MMPs in tumor invasion, neoangiogenesis, and metastasis, and therefore they represent ideal pharmacologic targets for cancer therapy. From the 1990s to early 2000s, synthetic inhibitors of MMPs (MMPI) were studied in various cancer types. Unexpectedly, despite strongly promising preclinical data, all trials were unsuccessful in reducing tumor burden or improving overall survival; in addition, MMPIs had unforeseen, severe side effects. Two main reasons can explain the failure of MMPIs in clinical trials. It has now become apparent that some MMPs have antitumor effects; therefore, the broad-spectrum MMPIs used in the initial trials might block these MMPs and result in tumor progression. In addition, although MMPs are involved in the early stages of tumor progression, MMPIs were tested in patients with advanced disease, beyond the stage when these compounds could be effective. As more specific MMPIs are now available, MMP targeting could be reconsidered for cancer therapy; however, new trials should be designed to test their antimetastatic properties in early-stage tumors, and endpoints should focus on parameters other than decreasing metastatic tumor burden. Mol Cancer Ther; 17(6); 1147-55. ©2018 AACR.

Bone turnover biomarkers identify unique prognostic risk groups in men with castration resistant prostate cancer and skeletal metastases: Results from SWOG S0421

BACKGROUND

Skeletal metastases often occur in men with castration-resistant prostate cancer (CRPC) where bone biomarkers are prognostic for overall survival (OS). In those with highly elevated markers, there is preferential benefit from bone-targeted therapy. In the phase IIIS0421 docetaxel +/- atrasentan trial, clinical covariates and bone biomarkers were analyzed to identify CRPC subsets with differential outcomes.

SUBJECTS AND METHODS

Markers of bone resorption [N-telopeptide-NTx; pyridinoline-PYD] and formation [C-terminal collagen propeptide-CICP; bone alkaline phosphatase-BAP] were measured in pre-treatment sera. Bone biomarkers and clinical covariates were included in a Cox model for OS; bone markers were added in a stepwise selection process. Receiver operating characteristic (ROC) curves were constructed for risk factor models +/- bone markers. Significant variables were allowed to compete in a classification and regression tree (CART) analysis. Hazard ratios(HR) were calculated by comparing OS in each of the terminal nodes to a reference group in a Cox model.

RESULTS

750 patients were included. Each bone marker significantly contributed to the risk factor-adjusted OS Cox model, with higher levels associated with worse OS. BAP (HR = 1.15, p = 0.008), CICP (HR = 1.27, p < 0.001), and PYD (HR = 1.21, p = 0.047) in combination were significantly associated with OS. Prognostic accuracy was improved by addition of bone markers to clinical covariates. CART analysis selected CICP, BAP, hemoglobin, and pain score for the final OS model, identifying five prognostic groups.

CONCLUSIONS

Elevated serum bone biomarker levels are associated with worse OS in bone-metastatic CRPC. Bone biomarkers can identify unique prognostic subgroups. These results further define the role of bone biomarkers in the design of CRPC trials.

Bone turnover markers in serum and urine as diagnostic, prognostic and monitoring biomarkers of bone metastasis

Bone metastases are characterized by increased osteoblastic and/or osteolytic processes depending on the tumor type. The altogether destructive effect of metastasis formation promoted by increased metabolic activity raises the release of components from the osseous metabolism into the blood stream. These components are either enzymes directly involved in the alteration processes, metabolites/proteins that develop during this or bone matrix proteins released during this. These biomarkers are categorized in relation to their involvement in the bone formation or resorption as bone formation and resorption markers. Based on a PubMed literature search, a critical appraisal of the various biomarkers for diagnostic, prognostic, and monitoring purposes is given for patients with skeletal metastases caused by breast, prostate, lung, or renal cell carcinomas.

Serum biomarkers of bone metabolism in castration-resistant prostate cancer patients with skeletal metastases: results from SWOG 0421

BACKGROUND

Prior studies suggest that elevated markers of bone turnover are prognostic for poor survival in castration-resistant prostate cancer (CRPC). The predictive role of these markers relative to bone-targeted therapy is unknown. We prospectively evaluated the prognostic and predictive value of bone biomarkers in sera from CRPC patients treated on a placebo-controlled phase III trial of docetaxel with or without the bone targeted endothelin-A receptor antagonist atrasentan (SWOG S0421).

METHODS

Markers for bone resorption (N-telopeptide and pyridinoline) and formation (C-terminal collagen propeptide and bone alkaline phosphatase) were assayed in pretreatment and serial sera. Cox proportional hazards regression models were fit for overall survival. Models were fit with main effects for marker levels and with/without terms for marker-treatment interaction, adjusted for clinical variables, to assess the prognostic and predictive value of atrasentan. Analysis was adjusted for multiple comparisons. Two-sided P values were calculated using the Wald test.

RESULTS

Sera from 778 patients were analyzed. Elevated baseline levels of each of the markers were associated with worse survival (P < .001). Increasing marker levels by week nine of therapy were also associated with subsequent poor survival (P < .001). Patients with the highest marker levels (upper 25th percentile for all markers) not only had a poor prognosis (hazard ratio [HR] = 4.3; 95% confidence interval [CI] = 2.41 to 7.65; P < .001) but also had a survival benefit from atrasentan (HR = 0.33; 95% CI = 0.15 to 0.71; median survival = 13 [atrasentan] vs 5 months [placebo]; P interaction = .005).

CONCLUSIONS

Serum bone metabolism markers have statistically significant independent prognostic value in CRPC. Importantly, a small group of patients (6%) with highly elevated markers of bone turnover appear to preferentially benefit from atrasentan therapy.

Pigment epithelium-derived factor as a natural matrix metalloproteinase inhibitor: a comparison with classical matrix metalloproteinase inhibitors used for cancer treatment

OBJECTIVES

In the 1990s, the discovery of the important role of matrix metalloproteinases (MMPs) in cancer angiogenesis, growth and metastasis galvanised research efforts to search for ways to inhibit these MMPs. To date, this has resulted in the investigation of approximately 50 MMPIs which have undergone various phases of clinical trials. However, despite a large body of research being devoted to discovery and development of MMPIs, results have largely not been supportive of this approach to anticancer treatment.

KEY FINDINGS

The reasons for the general failure of these drugs in clinical trials include various unwanted side-effects, the use of healthy volunteers to provide drug dosages which did not correctly reflect dosages for cancer patients, and the exclusion of patients with early stage cancer in clinical trials despite MMPs being determined to be critical for the angiogenic switch, a process associated with early tumour growth. In contrast, a naturally-occurring endogenous protein and a non-functional serine protease inhibitor (serpin), pigment epithelium-derived factor (PEDF), has been proposed for cancer therapy partly due to its ability to regulate specific MMPs central to cancer progression.

SUMMARY

PEDF has been found to specifically downregulate membrane-type I matrix metalloproteinase (MT1-MMP) and furthermore, potentially matrix metalloproteinase-2 (MMP-2), two of the most commonly implicated MMPs in neoplasia.

Procollagen assays in cancer

The synthesis rates of fibrillar collagens can be assessed in blood by measuring propeptides set free from corresponding procollagens before fiber formation. Type I collagen is the major component of the organic matrix of bone, but it is also found in other connective tissues. The serum concentration of the amino-terminal propeptide of type I procollagen, PINP, functions as a measure of type I collagen synthesis during normal bone turnover, but it is also released from bone metastases that involve an osteoblastic component. Type III collagen is a major constituent of soft tissues and the corresponding amino-terminal propeptide, PIIINP, reflects collagen synthesis. Circulating PIIINP tends to be affected by malignomas that grow in the peritoneal cavity or affect bone marrow. Many studies on procollagen markers in cancer have been cross-sectional or demonstrated treatment effects in patient groups. Markers that originate from bone turnover have wide reference intervals, but low biologic variability in individuals. Thus, they appear better suited for monitoring versus diagnostic purposes. There is still definite need for research on the use of procollagen markers in the followup of individual patients undergoing cancer treatment or being monitored after such treatment.

Targeting angiogenesis for treatment of human cancer

Recent advances in cancer research highlighted the importance of target-specific drug discovery. In view of these advances, the most important mechanism in tumour growth is its ability to stimulate the formation of blood capillaries around itself called tumour-driven angiogenesis. Hence targeting the angiogenesis, inhibits the growth of blood vessels around it and responsible for death of the tumour due to starvation and accumulation of toxic waste. The therapy, thus, indirectly cytotoxic to the tumour cells by targeting newly developing blood vessels. In this review, we summarised the various antiangiogenic agents with their clinical uses and current status.

Potential clinical applications of matrix metalloproteinase inhibitors and their future prospects

Matrix metalloproteinases (MMPs) are endopeptidases that are involved in extracellular matrix degradation. They are also implicated in a number of abnormal bioprocesses, such as tumor growth, invasion, and metastasis. Therefore, controlling MMP activities has generated considerable interest as a possible therapeutic target. The tissue inhibitors of metalloproteinases (TIMPs) are the major naturally occurring proteins that specifically inhibit MMPs and assist in maintaining the balance between extracellular matrix destruction and formation. However, TIMPs are probably not suitable for pharmacological applications due to their short half-lives in vivo. During the last few decades, synthetic MMP inhibitors (MMPIs) have undergone rapid clinical development in attempts to control MMP enzymatic activities in abnormal bioprocesses. Although studies with these agents have met with limited clinical success, the field of MMPIs is still expanding, and generation of highly effective and selective MMPIs might be a promising direction of this research area.

Matrix metalloproteinase-2 as a target for head and neck cancer therapy

INTRODUCTION

Matrix metalloproteinase (MMP)-2 is a zinc-dependent proteinase that is capable of cleaving all extracellular matrix (ECM) substrates. Degradation of the matrix is a key event in the progression, invasion, and metastasis of potentially malignant and malignant lesions of the head and neck. Therefore, blocking MMP-2 expression or activity may present a promising strategy for anticancer treatment.

AREAS COVERED

Current understanding of the molecular mechanisms that govern MMP-2 regulation and its tumorigenic effects, and that are involved in the initiation and progression of head and neck cancers, in particular the emerging role of MMP-2 in cell migration, which is a prerequisite for tumor metastasis. MMP-2 gene polymorphisms, cellular substrates, and interacting proteins are summarized. The current state of drugs that target this enzyme, either alone or in combination with other targeted agents are also discussed.

EXPERT OPINION

MMP-2 has long been a drug target. The current status of MMP-2 inhibitors as anticancer agents and their failure in the clinic is discussed in light of new data on the MMP-2s role as a cell surface transducer - data that may lead to the design and development of novel, MMP-2-targeting inhibitors.

Targeting tumor cell motility to prevent metastasis

Mortality and morbidity in patients with solid tumors invariably result from the disruption of normal biological function caused by disseminating tumor cells. Tumor cell migration is under intense investigation as the underlying cause of cancer metastasis. The need for tumor cell motility in the progression of metastasis has been established experimentally and is supported empirically by basic and clinical research implicating a large collection of migration-related genes. However, there are few clinical interventions designed to specifically target the motility of tumor cells and adjuvant therapy to specifically prevent cancer cell dissemination is severely limited. In an attempt to define motility targets suitable for treating metastasis, we have parsed the molecular determinants of tumor cell motility into five underlying principles including cell autonomous ability, soluble communication, cell-cell adhesion, cell-matrix adhesion, and integrating these determinants of migration on molecular scaffolds. The current challenge is to implement meaningful and sustainable inhibition of metastasis by developing clinically viable disruption of molecular targets that control these fundamental capabilities.

Bone turnover markers as predictors of mortality risk in prostate cancer patients with bone metastases following treatment with zoledronic acid

BACKGROUND

Clinical data have limited validity for predicting the survival of prostate cancer (PCa) patients with bone metastases. There is a need to improve the predictive evidence both for clinicians and patients.

OBJECTIVE

To evaluate the predictive ability of serum bone markers for mortality risk in PCa patients with bone metastases.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a survival analysis in relation to bone markers in a subgroup of 52 patients treated with zoledronic acid (4 mg every 4 wk for 15 mo) in a prospective, multicentre trial during 2002-2005, about 4 yr after the end of the trial.

MEASUREMENTS

Serum levels of total and bone-specific alkaline phosphatase, amino-terminal procollagen propeptides of type I collagen (PINP), cross-linked N-terminal (NTx) and cross-linked C-terminal telopeptides of type I collagen (ICTP), C-terminal telopeptides of type I collagen, prostate-specific antigen from the last visit of the treatment study, and clinical data were related to the overall survival (OS) status of patients in the follow-up. Univariate and multivariate Cox regression analyses with internal bootstrapping validation and concordance index calculations were performed.

RESULTS AND LIMITATIONS

Out of the 52 patients followed, 34 died within a median follow-up of 13.8 mo, and 18 patients were alive at a median follow-up of 43.8 mo. The patients who died within the follow-up period had significantly higher concentrations of ICTP, NTx, and PINP than the surviving patients. Cox regression models with clinical data and bone markers showed that ICTP and PINP were most predictive for mortality risk in addition to the occurrence of skeletal-related complications and the continuation of treatment with zoledronic acid. Internal validation confirmed the reliability of the results, although the sample size was small.

CONCLUSIONS

PINP and ICTP can be considered suitable predictors for the OS of PCa patients with bone metastases.

Jekyll and Hyde: the role of the microenvironment on the progression of cancer

It is now recognized that the host microenvironment undergoes extensive change during the evolution and progression of cancer. This involves the generation of cancer-associated fibroblasts (CAFs), which, through release of growth factors and cytokines, lead to enhanced angiogenesis, increased tumour growth and invasion. It has also been demonstrated that CAFs may modulate the cancer stem cell (CSC) phenotype, which has therapeutic implications. The altered fibroblast phenotype also contributes to the development of an altered extracellular matrix (ECM), with synthesis of ECM isoforms rarely found in normal tissues, including tenascin-C isoforms and the fibronectin EDA isoform. There is also emerging evidence of how the tensile strength of the tumour-associated ECM may be modified and lead to altered signalling in tumour cells. The hypoxic environment of the tumour stimulates angiogenesis and also impacts on other aspects of cell signalling, including the c-met pathway and lysyl oxidase-mediated signalling, which can directly promote tumour cell invasion. The inflammatory infiltrate associated with many solid tumours also modulates tumour function, having both anti- and pro-tumour effects. All of these components of the microenvironment provide potential targets for therapeutic attack, with a number of molecules already in clinical trials. It is also becoming evident that characterizing the tumour microenvironment can provide important prognostic and predictive information about tumours, independent of the tumour cell phenotype.

Orally active MMP-1 sparing α-tetrahydropyranyl and α-piperidinyl sulfone matrix metalloproteinase (MMP) inhibitors with efficacy in cancer, arthritis, and cardiovascular disease

α-Sulfone-α-piperidine and α-tetrahydropyranyl hydroxamates were explored that are potent inhibitors of MMP's-2, -9, and -13 that spare MMP-1, with oral efficacy in inhibiting tumor growth in mice and left-ventricular hypertrophy in rats and in the bovine cartilage degradation ex vivo explant system. α-Piperidine 19v (SC-78080/SD-2590) was selected for development toward the initial indication of cancer, while α-piperidine and α-tetrahydropyranyl hydroxamates 19w (SC-77964) and 9i (SC-77774), respectively, were identified as backup compounds.

Cilengitide (EMD 121974, NSC 707544) in asymptomatic metastatic castration resistant prostate cancer patients: a randomized phase II trial by the prostate cancer clinical trials consortium

BACKGROUND

Integrins are involved in prostate cancer metastasis by regulating cell adhesion, migration, invasion, motility, angiogenesis and bone metabolism. We evaluated the efficacy of two dose levels of cilengitide in patients (pts) with castrate resistant prostate cancer (CRPC).

METHODS

Chemotherapy-naïve, asymptomatic metastatic CRPC pts were randomized to cilengitide 500 mg or 2,000 mg IV twice weekly using parallel 2-stage design. The primary endpoint was rate of objective clinical progression at 6-months. Secondary endpoints included clinical and PSA response rates, safety and effects of cilengitide treatment on circulating tumor cells (CTCs) and bone remodeling markers.

RESULTS

Forty-four pts were accrued to first stage (22/arm). Median number of cycles was three in both arms (500 mg arm: 1-8; 2,000 mg arm: 1-15). At 6 months, two pts (9%) on the 500 mg arm and five pts (23%) on the 2,000 mg arm had not progressed. Best objective response was stable disease (SD) in seven pts for 9.9[8.1,20.9] months. There were three grade 3 and no grade 4 toxicities. At 12 weeks, analysis of bone markers did not reveal significant trends. At progression, bone specific alkaline phosphatase and N-telopeptide increased in all pts, less so in pts on the 2,000 mg arm and in pts on both arms who obtained SD at 6 months. CTCs increased over time in both arms.

CONCLUSION

Cilengitide was well tolerated with modest clinical effect in favor of the higher dose. The unique trial design including a shift from response rate to objective progression as the endpoint, and not acting on PSA increases was feasible.

Potential implications of matrix metalloproteinase-9 in assessment and treatment of coronary artery disease

BACKGROUND

Matrix metalloproteinase (MMP)-9, a member of the MMP superfamily is consistently implicated in the pathophysiology of atherosclerosis and plaque rupture, the most common mechanism responsible for acute coronary syndrome (ACS).

AIM

To summarize the role of MMP-9 in atherosclerosis and its potential implications in assessment and treatment of coronary artery disease (CAD).

METHODS

We reviewed the PubMed database for relevant data regarding the role of MMP-9 in the pathophysiology of atherosclerosis. In the light of these data, we postulate potential implications of MMP-9 in the management and treatment of CAD.

RESULTS AND CONCLUSIONS

Existing data strongly support the role of MMP-9 in plaque destabilization and rupture. Based on the current knowledge, MMP-9 can potentially serve as a diagnostic biomarker in ACS and a prognostic biomarker in ACS and chronic CAD patients. MMP-9 is reduced by therapies that are associated with favourable outcome in atherosclerosis and thus may serve as a surrogate biomarker of treatment efficacy. However, large morbidity and mortality trials are still required to confirm that MMP-9 reduction is associated with improved outcome independent of the traditional risk factors (i.e. low-density lipoprotein cholesterol). Given its role in plaque rupture, inhibition of MMP-9 may promote plaque stabilization and consequently reduce cardiovascular events. Yet, the efficacy and safety of MMPs inhibitors should be first studied in preclinical models of atherosclerosis.

Antiangiogenic drugs: current knowledge and new approaches to cancer therapy

Angiogenesis--process of new blood-vessel growth from existing vasculature--is an integral part of both normal developmental processes and numerous pathologies such as cancer, ischemic diseases and chronic inflammation. Angiogenesis plays a crucial role facilitating tumour growth and the metastatic process, and it is the result of a dynamic balance between proangiogenic and antiangiogenic factors. The potential to block tumour growth and metastases by angiogenesis inhibition represents an intriguing approach to the cancer treatment. Angiogenesis continues to be a topic of major scientific interest; and there are currently more antiangiogenic drugs in cancer clinical trials than those that fit into any other mechanistic category. Based on preclinical studies, researchers believe that targeting the blood vessels which support tumour growth could help treatment of a broad range of cancers. Angiogenic factors or their receptors, endothelial cell proliferation, matrix metalloproteinases or endothelial cell adhesion, are the main targets of an increasing number of clinical trials approved to test the tolerance and therapeutic efficacy of antiangiogenic agents. Unfortunately, contrary to initial expectations, it has been described that antiangiogenic treatment can cause different toxicities in cancer patients. The purpose of this article is to provide an overview of current attempts to inhibit tumour angiogenesis for cancer therapy.

Phase 1/2 trial of BMS-275291 in patients with human immunodeficiency virus-related Kaposi sarcoma: a multicenter trial of the AIDS Malignancy Consortium

BACKGROUND

Matrix metalloproteinases (MMPs) are overexpressed in Kaposi sarcoma (KS). The safety and efficacy of a novel, orally bioavailable MMP inhibitor, BMS-275291, was evaluated in patients with human immunodeficiency virus-associated KS and the correlation between changes in the percentage of apoptotic cells in tumor biopsies and response was explored.

METHODS

Cohorts of 6 patients were to be treated with BMS-275291. The initial cohort received 1200 mg once a day; subsequent doses were to be escalated to 600 mg twice daily and 1200 mg twice daily, or decreased to 600 mg/day. Tumor biopsies for apoptosis assays were collected pretreatment and on Day 29. Prospectively defined dose level adjustments were to be based on dose-limiting toxicity (DLT), tolerability, changes in the percentage of apoptotic cells, and treatment response.

RESULTS

Sixteen patients were enrolled; 15 received the study drug and could be evaluated. The median duration of treatment was 20 weeks (range, 3-54 weeks). A dose of 1200 mg once a day was well tolerated but induced only 1 response. A DLT occurred in 3 patients treated with 600 mg twice daily, and included grade 3 fatigue, grade 3 allergic reaction, and grade 3 arthralgias; 2 responses were noted at this dose level (toxicity was graded according to the National Cancer Institute Common Toxicity Criteria [version 2.0]). Based on predetermined endpoints, the trial was closed after accrual of 15 treated patients. Assessment of biologic response for dose escalation/de-escalation decisions utilizing the apoptosis assay was not feasible.

CONCLUSIONS

BMS-275291 given at a dose of 600 mg twice daily induced unacceptable toxicity. The better-tolerated schedule of 1200 mg once a day demonstrated inadequate efficacy in patients with human immunodeficiency virus-associated KS. The apoptosis assay was not helpful in predicting response.

Effect of interleukin-8 gene silencing with liposome-encapsulated small interfering RNA on ovarian cancer cell growth

BACKGROUND

Interleukin-8 (IL-8) is a proangiogenic cytokine that is overexpressed in many human cancers. We investigated the clinical and biologic significance of IL-8 in ovarian carcinoma using human samples and orthotopic mouse models.

METHODS

Tumor expression of IL-8 was assessed by immunohistochemistry among ovarian cancer patients (n = 102) with available clinical and survival data. We examined the effect of IL-8 gene silencing with small interfering RNAs incorporated into neutral liposomes (siRNA-DOPCs), alone and in combination with docetaxel, on in vivo tumor growth, angiogenesis (microvessel density), and tumor cell proliferation in mice (n = 10 per treatment group) bearing orthotopic taxane-sensitive (HeyA8 and SKOV3ip1) and taxane-resistant (SKOV3ip2.TR) ovarian tumors. All statistical tests were two-sided.

RESULTS

Of the 102 cancer specimens, 43 (42%) had high IL-8 expression and 59 (58%) had low or no IL-8 expression; high IL-8 expression was associated with advanced tumor stage (P = .019), high tumor grade (P = .031), and worse survival (median survival for patients with high vs low IL-8 expression: 1.62 vs 3.79 years; P < .001). Compared with empty liposomes, IL-8 siRNA-DOPC reduced the mean tumor weight by 32% (95% confidence interval [CI] = 14% to 50%; P = .03) and 52% (95% CI = 27% to 78%; P = .03) in the HeyA8 and SKOV3ip1 mouse models, respectively. In all three mouse models, treatment with IL-8 siRNA-DOPC plus the taxane docetaxel reduced tumor growth the most compared with empty liposomes (77% to 98% reduction in tumor growth; P < .01 for all). In the HeyA8 and SKOV3ip1 models, tumors from mice treated with IL-8 siRNA-DOPC alone had lower microvessel density than tumors from mice treated with empty liposomes (HeyA8: 34% lower, 95% CI = 32% to 36% lower [P = .002]; SKOV3ip1: 39% lower, 95% CI = 34% to 44% lower [P = .007]). Compared with empty liposomes, IL-8 siRNA-DOPC plus docetaxel reduced tumor cell proliferation by 35% (95% CI = 25% to 44%; P < .001) and 38% (95% CI = 28% to 48%; P < .001) in the HeyA8 and SKOV3ip1 models, respectively.

CONCLUSIONS

Increased IL-8 expression is associated with poor clinical outcome in human ovarian carcinoma, and IL-8 gene silencing decreases tumor growth through antiangiogenic mechanisms.

Fracture risk in Danish men with prostate cancer: a nationwide register study

OBJECTIVE

To assess the risk of fracture attributable to prostate cancer, and the impact of exposure to prescribed gonadotrophin-releasing hormone agonists and antiandrogens on this risk in a nationwide, population-based case-control study.

PATIENTS AND METHODS

Data from the Danish National Hospital Discharge Register, the National Bureau of Statistics, and the National Prescriptions Database were merged. The analysis covered 15 716 men aged >50 years presenting with a fracture at any hospital in Denmark in 2000, and 47 149 age-matched control men. A previous diagnosis of prostate cancer had been recorded in 1.3% of controls and 2.5% of those with a fracture.

RESULTS

Prostate cancer was associated with an increased odds ratio (95% confidence interval) for all fractures of 1.8 (1.6-2.1), for hip fractures of 3.7 (3.1-4.4), but no increased risk of vertebral fractures. The increased fracture risk became apparent early after diagnosis and remained pronounced even in long-term survivors. Androgen deprivation therapy (ADT) with an odds ratio of 1.7 (1.2-2.5; P < 0.01) and orchidectomy, at 1.7 (1.2-2.4; P < 0.01) added to the overall fracture risk. In all, 3.1% of hip fractures in Danish men aged >50 years are attributable to prostate cancer.

CONCLUSION

Prostate cancer, orchidectomy and the use of ADT are associated with a markedly greater risk of fractures, especially of the hip. The risk of hip fracture is not confined to the very old, neither is the risk made negligible by the excess mortality in patients with advanced prostate cancer.

Tumor metastasis to bone

Establishment of skeletal metastasis involves bidirectional interactions between the tumor cell and the cellular elements in the bone microenvironment. A better understanding of the pathophysiology of bone metastasis will be critical in developing the means to prevent bone metastasis or inhibit its progression. The receptor activator of nuclear factor-kappaB (RANK)/RANK ligand pathway has emerged as the key pathway regulating osteolysis in skeletal metastasis. A number of candidate factors, including the Wnt (wingless int) proteins, endothelin-1, and bone morphogenetic proteins, have been implicated in the establishment of osteoblastic metastasis. The complex nature of tumor-bone microenvironment interactions and the presence of multiple pathways that lead to bone metastasis suggests that simultaneous targeting of these pathways in the metastatic cascade are required for effective treatment. This review discusses current understanding of the pathophysiologic mechanisms that underlie the establishment of bone metastasis and potential molecular therapeutic strategies for prevention and treatment of bone metastasis.

Bone Directed Therapies for Prostate Cancer

PURPOSE

Bone is the most common site of metastatic disease in prostate cancer and the lead cause of significant morbidity. Preclinical and clinical studies have provided insight into the pathophysiology of bone metastases and the changes that occur in the bone microenvironment that result in a favorable site of growth for prostate cancer. We provide an overview of recent advances in understanding bone biology, and bone targeted therapy research and development.

MATERIALS AND METHODS

We reviewed recent research findings related to the biology of bone metastases, approaches to targeting osteoclast function, approaches to targeting osteoblasts and advances in assessing the treatment response to bone targeted therapies in the context of prostate cancer management.

RESULTS

To date targeting some of the key players in the bone microenvironment has not been associated with a significant antitumor effect or with meaningful clinical benefit in phase III randomized trials. A significant limitation in the development of bone targeted therapy has been the inability to objectively assess treatment response. Investigation of improved imaging techniques are ongoing to provide better treatment assessment and, therefore, allow more rapid drug screening and development.

CONCLUSIONS

It is our recommendation that future therapy development should be combination based, focusing on simultaneous targeting of multiple relevant pathways. Most important of all is the direct targeting of prostate cancer cells.

Suppression of bone density loss and bone turnover in patients with hormone-sensitive prostate cancer and receiving zoledronic acid

OBJECTIVE

To report a randomized, placebo-controlled study of treatment with zoledronic acid every 3 months in patients with hormone-sensitive prostate cancer, both with and without bone metastases, to assess the effect on bone mineral density (BMD) and markers of bone turnover.

PATIENTS AND METHODS

Eligible patients included those with prostate cancer and on androgen-deprivation therapy for <12 months. Patients received zoledronic acid 4 mg intravenously, or placebo, every 3 months for four treatments. BMD, urinary N-telopeptides of type I collagen (NTX), and serum bone alkaline phosphatase (BAP) were measured every 3 months. In all, 42 patients were randomized.

RESULTS

After excluding BMD data from sites of known metastases, patients receiving zoledronic acid had a relative increase in BMD compared with those receiving placebo, of 4.2% and 7.1% at the femoral neck and lumbar spine, respectively. NTX and BAP decreased significantly in patients receiving zoledronic acid. NTX and BAP levels were significantly higher at baseline in patients with bone metastases than in those without.

CONCLUSIONS

Treatment with zoledronic acid every 3 months preserved bone density and suppressed markers of bone turnover in patients with androgen-deprived prostate cancer, both with and without bone metastases.

MMPs as therapeutic targets--still a viable option?

Matrix metalloproteinases (MMPs) appear to be ideal drug targets--they are disease-associated, extracellular enzymes with a dependence on zinc for activity. This apparently straightforward target, however, is much more complex than initially realized. Although disease associated, the roles for particular enzymes may be healing rather than harmful making broad-spectrum inhibition unwise; targeting the catalytic zinc with specificity is difficult, since other related proteases as well as non-related proteins can be affected by some chelating groups. While the failure of early-generation MMP inhibitors dampened enthusiasm for this type of drug, there has recently been a wealth of studies examining the basic biology of MMPs which will greatly inform new drug trials in this field.

Prostate cancer and markers of bone metabolism: diagnostic, prognostic, and therapeutic implications

Knowledge of bone metastases complicating advanced prostate cancer (CaP) is increasingly relevant in patient selection for novel therapies. Current nuclear bone scintigraphy imaging has limited specificity for prostate metastases. As serum bone markers do correlate with bony lesions, they may play multiple roles in patients with advanced CaP. Currently, these markers play a role in prognostic nomograms for CaP. Recent studies suggest an expanding role for bone markers in the diagnosis and selection of patients for novel therapies. In the future, therapeutic roles for some of these marker pathways will emerge, eventually allowing greater individualization of patient care.

Therapeutic options to target angiogenesis in human malignancies

The critical role of angiogenesis in tumour growth and metastasis is now well established in the literature. Growing tumours stimulate neovascularisation through the secretion of pro-angiogenic growth factors, in particular, basic fibroblast growth factor and VEGF. Several lines of evidence have implicated VEGF in tumourigenesis, and understanding the role of VEGF in tumour angiogenesis has facilitated the development of novel targeting agents that specifically interfere with angiogenesis. Different approaches to disrupting tumour-induced angiogenesis encompass tyrosine kinase inhibitor, monoclonal antibodies, small-molecule inhibitors and transcription inhibitors. However, monoclonal antibody and tyrosine kinase inhibitors are the most advanced drug classes currently being investigated in clinical trials. So far, three anti-VEGF inhibitors, bevacizumab, sunitinib and sorafenib, have been approved for the treatment of solid human malignancies including colorectal cancer, gastrointestinal stromal tumours and renal cell carcinoma. Other antiangiogenic drugs are being investigated in various types of cancer. This review summarises the current literature on the use of these agents to interfere with VEGF, VEGF receptor, the matrix breakdown or other mechanisms involved in angiogenesis.

Adenovirus-mediated small interfering RNA against matrix metalloproteinase-2 suppresses tumor growth and lung metastasis in mice

Matrix metalloproteinases (MMP) are a group of proteinases that have normal physiologic roles degrading and remodeling the extracellular matrix. They also have multiple roles in different stages of tumor progression. Elevated levels of MMPs have been observed in many tumors; these increases have a strong association with the invasive phenotype. MMP-2 and MMP-9 are particularly involved in cancer invasion and metastasis. MMP inhibitors are currently being tested as therapeutic agents for a number of cancers in both preclinical models and in clinical trials. To date, clinical trials using this strategy have had limited efficacy. A major concern is the lack of specificity of commercially available MMP inhibitors. An adenoviral vector expressing small interfering RNA against the MMP-2 gene (Ad-MMP-2) was constructed to specifically inhibit MMP-2 expression. The effect of Ad-MMP-2 on invasion, angiogenesis, tumor growth, and metastasis of A549 lung cancer cell was evaluated. Ad-MMP-2 infection of lung cancer cells showed specific down-regulation of MMP-2 protein, activity, and transcription as determined by Western blotting, gelatin zymography, and reverse transcription-PCR. Ad-MMP-2 inhibition also mitigated lung cancer invasion and migration, and reduced tumor cell-induced angiogenesis in vitro. In an experimental metastatic lung tumor model, treatment of established tumors by Ad-MMP-2 inhibited s.c. tumor growth and formation of lung nodules in mice. Adenoviral-mediated RNA interference against MMP-2 has significant therapeutic potential for lung cancer and exerts some of this effect by inhibiting angiogenesis.

Anti-angiogenic drugs: from bench to clinical trials

Angiogenesis, the generation of new capillaries through a process of pre-existing microvessel sprouting, is under stringent control and normally occurs only during embryonic and post-embryonic development, reproductive cycle, and wound repair. However, in many pathological conditions (solid tumor progression, metastasis, diabetic retinopathy, hemangioma, arthritis, psoriasis and atherosclerosis among others), the disease appears to be associated with persistent upregulated angiogenesis. The development of specific anti-angiogenic agents arises as an attractive therapeutic approach for the treatment of cancer and other angiogenesis-dependent diseases. The formation of new blood vessels is a complex multi-step process. Endothelial cells resting in the parent vessels are activated by an angiogenic signal and stimulated to synthesize and release degradative enzymes allowing endothelial cells to migrate, proliferate and finally differentiate to give rise to capillary tubules. Any of these steps may be a potential target for pharmacological intervention. In spite of the disappointing results obtained initially in clinical trials with anti-angiogenic drugs, recent reports with positive results in phases II and III trials encourage expectations in their therapeutic potential. This review discusses the current approaches for the discovery of new compounds that inhibit angiogenesis, with emphasis on the clinical developmental status of anti-angiogenic drugs.

The metastatic cascade in prostate cancer

Morbidity and mortality due to prostate cancer are mainly a result of prostate cancer metastases. After the initial neoplastic transformation of cells, the process of metastasis involves a series of sequential steps, which involve neoangiogenesis and lymphangiogenesis, loss of adhesion with migration away from the primary tumour and entry into the systemic vasculature or lymphatics. Metastatic growth in sites such as lymph nodes and bone marrow then involves the specific non-random homing of prostate cancer cells. An appreciation and understanding of this metastatic cascade in relation to prostate cancer is clinically important in order to stratify men with prostate cancer into prognostic groups. Moreover, it is crucial in the future development of therapies that can prevent metastases.