Molecular and cellular biomarkers for angiogenesis in clinical oncology

Effectiveness and toxicity of metronomic oral cyclophosphamide for recurrent or platinum-refractory ovarian cancer: A meta-analysis

Purpose

To systematically assess the effectiveness and toxicity of metronomic oral cyclophosphamide (MOC) on recurrent or platinum-refractory ovarian cancer.

Methods

We searched the Cochrane Library, Embase, PubMed, CNKI, Weipu, and Wanfang databases for eligible studies. A descriptive statistical method was used to analyze the pooled results. Ratios and means were merged to analyze the objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and the rate of serious adverse events (SAEs). Subgroup analysis, sensitivity analysis, and examination of publication bias were conducted for heterogeneity test and quality assurance of the results.

Results

The ORR and DCR by MOC were 25% (95% CI 12–41) and 61% (95% CI 43–77), respectively. The median PFS and OS were 4.29 months (95% CI 2.62–5.97) and 11.26 months (95% CI 8.13–14.39), respectively. The rate of SAEs was 41% (95% CI 30–52). The most frequent SAEs were gastrointestinal toxicity 6% (95% CI 1–12), lymphopenia 6% (95% CI 1–13), and neutropenia 5% (95% CI 2–9). In the subgroup analysis, the ORR and DCR in the subgroup of MOC combined with bevacizumab/pazopanib were 42% (95% CI 26–58) and 82% (95% CI 63–95), respectively. The median PFS and OS were 7.32 months (95% CI 5.93–8.70) and 17.35 months (95% CI 12.89–21.82), respectively.

Conclusion

MOC has a certain effect in clinical response on patients with recurrent or platinum-refractory ovarian cancers, especially when MOC combined with bevacizumab/pazopanib. However, there is a high risk of SAEs.

Biguanides decorated albumin nanoparticles loading nintedanib for synergic enhanced hepatocellular carcinoma therapy

Nintedanib (ND) was known as a triple tyrosine kinase inhibitors, inhibiting angiogenesis and tissue fibrosis. Biguanide group has attracted much attention for its great penetrating ability to the lipid bilayer of cytomembrane and potential anti-cancer efficacy. In this study, a biguanide group (p-biguanidinobenzoic acid, CBH) decorated bovine serum albumin (CBH-AB) was synthesized as a novel functional biomaterial to prepare the ND loaded CBH-AB nanoparticles (ND-CBH-AB NPs). The results of physical and chemical properties showed that ND-CBH-AB NPs possessed high encapsulation efficiency and drug loading efficiency. In vitro cell study indicated that CBH modification on ND-CBH-AB NPs enhanced the cyctotoxicities to HepG2 cells. Furthermore, pharmacokinetic study showed that ND-CBH-AB NPs had good stability in circulation. Finally, pharmacodynamic studies were conducted, the results indicated that ND-CBH-AB NPs exhibited excellent anti-tumor effect and tumor microenvironment regulation effect. Thereby, this work provides a potential function albumin delivery system for hepatocellular carcinoma therapy.

Hypoxic tumor microenvironment: Implications for cancer therapy

IMPACT STATEMENT

Hypoxia contributes to tumor aggressiveness and promotes growth of many solid tumors that are often resistant to conventional therapies. In order to achieve successful therapeutic strategies targeting different cancer types, it is necessary to understand the molecular mechanisms and signaling pathways that are induced by hypoxia. Aberrant tumor vasculature and alterations in cellular metabolism and drug resistance due to hypoxia further confound this problem. This review focuses on the implications of hypoxia in an inflammatory TME and its impact on the signaling and metabolic pathways regulating growth and progression of cancer, along with changes in lymphangiogenic and angiogenic mechanisms. Finally, the overarching role of hypoxia in mediating therapeutic resistance in cancers is discussed.

Optimized multiparametric flow cytometric analysis of circulating endothelial cells and their subpopulations in peripheral blood of patients with solid tumors: a technical analysis

Background

Circulating endothelial cells (CECs) and their subpopulations could be potential novel biomarkers for various malignancies. However, reliable enumerable methods are warranted to further improve their clinical utility. This study aimed to optimize a flow cytometric method (FCM) assay for CECs and subpopulations in peripheral blood for patients with solid cancers.

Patients and methods

An FCM assay was used to detect and identify CECs. A panel of 60 blood samples, including 44 metastatic cancer patients and 16 healthy controls, were used in this study. Some key issues of CEC enumeration, including sample material and anticoagulant selection, optimal titration of antibodies, lysis/wash procedures of blood sample preparation, conditions of sample storage, sufficient cell events to enhance the signal, fluorescence-minus-one controls instead of isotype controls to reduce background noise, optimal selection of cell surface markers, and evaluating the reproducibility of our method, were integrated and investigated. Wilcoxon and Mann–Whitney U tests were used to determine statistically significant differences.

Results

In this validation study, we refined a five-color FCM method to detect CECs and their subpopulations in peripheral blood of patients with solid tumors. Several key technical issues regarding preanalytical elements, FCM data acquisition, and analysis were addressed. Furthermore, we clinically validated the utility of our method. The baseline levels of mature CECs, endothelial progenitor cells, and activated CECs were higher in cancer patients than healthy subjects (P<0.01). However, there was no significant difference in resting CEC levels between healthy subjects and cancer patients (P=0.193).

Conclusion

We integrated and comprehensively addressed significant technical issues found in previously published assays and validated the reproducibility and sensitivity of our proposed method. Future work is required to explore the potential of our optimized method in clinical oncologic applications.

Circulating endothelial cells and their subsets: novel biomarkers for cancer

Angiogenesis contributes to the growth of solid tumors. Antiangiogenic agents are widely used in various cancers and considerable efforts have been made in the development of novel biomarkers that can predict the outcome of an anticancer treatment. Of those, circulating endothelial cells (CECs) and their subsets constitute a surrogate tool for monitoring disease activity. However, owing to the lack of standardization on the phenotypes and detection of CECs and their subsets, results have always been inconsistent and uninterpretable. In this review, we focus on the biological characteristics in terms of physiology, phenotypes and detection of CECs along with their subsets; review the current scenario of CEC enumeration as a surrogate biomarker in clinical oncology; and explore their future potential applications.

Classical Kaposi sarcoma: case reports with unusual presentation on the penis and scrotum

BACKGROUND

Kaposi sarcoma (KS) is the most common vascular neoplasm. Any skin area could be involved, including the genitalia. Traditionally, classic KS lesions have a general distribution, often involving skin of the feet and legs, and to a lesser extent, that of the hands, arms, and trunk. KS limited to the external genitalia is extremely rare in HIV seronegative individuals.

METHODS

We report six patients of classic KS with generalized dermal KS lesions.

RESULTS

Two of them presenting with unusual KS lesions on the penis and scrotum beside the other dermal lesions. Patients were HIV negative and human herpes virus eight positive. Histological examination showed classical KS.

CONCLUSIONS

Primary KS of the penis and scrotum is rare but could occur in HIV-negative patients.

Circulating endothelial cells for evaluation of tumor response in non-small cell lung cancer patients receiving first-line chemotherapy

BACKGROUND

Circulating endothelial cells (CECs) reflect the neovascularization in the tumor mass. We therefore investigated the potential role of CEC kinetics after first-line chemotherapy in advanced non-small cell lung cancer (NSCLC) patients.

METHODS

Peripheral blood samples were obtained from 45 healthy subjects and 51 naïve patients with advanced NSCLC. Quantification of CD146+ CECs was performed using immunomagnetic separation (IMS).

RESULTS

Pretreatment and posttreatment CEC levels in NSCLC patients were significantly higher than in healthy subjects (p&lt;0.0001). An objective response was achieved after chemotherapy with partial response (PR) or stable disease (SD) in 26 patients, whereas the remaining 25 patients had progressive disease (PD). Baseline CEC levels were significantly higher in PR/SD patients than in PD patients (p = 0.039). After chemotherapy, CEC count significantly decreased in PR/SD patients (p = 0.014) and increased in patients with PD (p = 0.019). Moreover, there was a significant difference in the percentage change of CEC counts between the 2 groups (p = 0.0016). No significant difference in the median progression-free survival and overall survival (OS) was observed between patients with high baseline CEC counts and those with low baseline CEC levels. However, patients with high percentage change in CEC count had longer OS than those with low percentage change after chemotherapy (p = 0.05).

CONCLUSIONS

Changes in CEC counts after chemotherapy reflect tumor response in advanced NSCLC patients. Moreover, high percentage changes in CEC counts after chemotherapy may predict longer OS in advanced NSCLC. High baseline CEC levels might be an indicator of tumor response in advanced NSCLC patients after first-line chemotherapy.

Metronomic chemotherapy from rationale to clinical studies: a dream or reality?

Metronomic chemotherapy (MC) refers to the close administration of a chemotherapeutic drug for a long time with no extended drug-free breaks. It was developed to overcome drug resistance, partly by shifting the therapeutic target from tumor cells to the tumor vasculature, with less toxicity. Because of this peculiar way of administration, MC can be viewed as a form of long-term 'maintenance' treatment, and can be integrated with standard and conventional chemotherapy in a "chemo-switching" strategy. Additional mechanisms are involved in its antitumor activity, such as activation of immunity, induction of tumor dormancy, chemotherapy-driven dependency of cancer cells, and the '4D effect'. In this paper we report the most important studies that have analyzed these processes. In fact, a number of preclinical and clinical studies in solid tumors as well as in multiple myeloma, have been reported regarding several chemotherapy drugs which have been proposed with a metronomic schedule: vinorelbine, cyclophosphamide, capecitabine, methotrexate, bevacizumab, etoposide, gemcitabine, sorafenib, everolimus and temozolomide. The results of these studies have been sometimes conflicting, highlighting the need to develop reliable tools for patient selection and stratification. However, a more precise evaluation of MC strategies with the ongoing randomized phase II/III clinical is fundamental, because of the strict correlation of this approach with translational research and target therapy. Moreover, because of the low toxicity of MC, these studies will also help to better evaluate the clinical benefit of this treatment, with a special focus on elderly and low performance status patients.

Circulating endothelial cells and their subpopulations: role as predictive biomarkers in antiangiogenic therapy for colorectal cancer

Several anticancer therapies have been developed to block angiogenesis, a key mechanism in tumor growth and metastasis. The predominantly cytostatic action of these compounds makes an assessment of their clinical activities inadequate if based only on the reduction of the tumor dimensions, as this may not reflect their true biologic efficacy. Thus, it is crucial to identify biomarkers that permit the recognition of potentially responsive subjects and to spare toxicity in those who are unlikely to benefit from treatment. Circulating endothelial cells (CECs) have been recently indicated as potential surrogate biomarkers of angiogenesis in several types of cancer. The possibility of rapidly quantifying these cells represents a promising tool for monitoring the clinical outcome of tumors with the potential to assess response to various treatments. However, the identification and quantification of CECs is technically difficult and not well standardized. A variety of methods to detect CECs in patients with solid tumors have been used; these are based on different technical approaches, combinations of surface markers, sample handling, and staining protocols. With an expanding interest in the field of potential clinical applications for CECs in oncology, the development of standardized protocols for analysis is mandatory. The aim of this review was to critically summarize the available data concerning the clinical value of CECs and their subpopulations as biomarkers of antiangiogenic therapy in patients with metastatic colorectal cancer.

Revisiting cardiovascular regeneration with bone marrow-derived angiogenic and vasculogenic cells

Cell-based therapy has emerged as a promising therapy for cardiovascular disease. Particularly, bone marrow (BM)-derived cells have been most extensively investigated and have shown encouraging results in preclinical studies. Clinical trials, however, have demonstrated split results in post-myocardial infarction cardiac repair. Mechanistically, transdifferentiation of BM-derived cells into cardiovascular tissue demonstrated by earlier studies is now known to play a minor role in functional recovery, and humoral and paracrine effects turned out to be main mechanisms responsible for tissue regeneration and functional recovery. With this advancement in the mechanistic insight of BM-derived cells, new efforts have been made to identify cell population, which can be readily isolated and obtained in sufficient quantity without mobilization and have higher therapeutic potential. Recently, haematopoietic CD31(+) cells, which are more prevalent in bone marrow and peripheral blood, have been revealed to have angiogenic and vasculogenic activities and strong potential for therapeutic neovascularization in ischaemic tissues. This article will cover the recent advances in BM-derived cell-based therapy and implication of CD31(+) cells.

Endothelial CD276 (B7-H3) expression is increased in human malignancies and distinguishes between normal and tumour-derived circulating endothelial cells

Background:

Mature circulating endothelial cells (CEC) are surrogate markers of endothelial damage. CEC measured in patients with advanced cancer are thought not only to derive from damaged normal vasculature (n-CEC), but also from damaged (t-CEC). Therefore, assays that allow the discrimination between these two putative types of CEC are thought to improve the specificity of the enumeration of CEC in cancer.

Methods:

Identification of tumour-associated endothelial markers (TEM) by comparing antigen expression on normal vs t-CEC and assess the presence of t-CEC in peripheral blood of cancer patients by incorporating TEM in our novel flow cytometry-based CEC detection assay.

Results:

No difference in antigen expression between normal and malignant endothelial cells (ECs) was found for CD54, CD109, CD137, CD141, CD144 and CXCR7. In contrast, overexpression for CD105, CD146, CD276 and CD309 was observed in tumour ECs compared with normal ECs. CD276 was most differentially expressed and chosen as a marker for further investigation. CD276-expressing CEC were significantly higher in 15 patients with advanced colorectal cancer (median 9 (range 1–293 cell per 4 ml); P<0.005), in 83 patients with a glioblastoma multiforme (median 10 (range 0–804); P<0.0001) and in 14 patients with advanced breast cancer (median 14 (range 0–390) P<0.05) as compared with 24 healthy individuals (median 3 (range 0–11)). Of all patients with malignancies, 58% had CD276⁺ CEC counts above the ULN (8 cell per 4 ml).

Conclusions:

The present study shows that CD276 can be used to discriminate ECs from malignant tissue from ECs from normal tissue. In addition, CD276⁺ CEC do occur in higher frequencies in patients with advanced cancer.

Low-dose metronomic chemotherapy: a systematic literature analysis

Low-dose metronomic (LDM) chemotherapy, the frequent and continuous use of low doses of conventional chemotherapeutics, is an emerging alternative to conventional chemotherapy. While promising tumour control rates and excellent safety profiles have been observed, there are no definitive phase III trial results. Furthermore, the selection of patients, drug dosages and dosing intervals is empirical. To systematically review the current state of knowledge regarding LDM chemotherapy, we searched the MEDLINE, EMBASE, CENTRAL and PubMed databases for fully published LDM chemotherapy trials. We calculated the relative dose-intensity (RDI, mg/m(2)/week) of each LDM regimen as compared to conventional maximum tolerated dose (MTD) dosages and the 'dosing-density' (DD, % of days with chemotherapy administration per cycle). Meta-regression was performed to examine factors associated with disease control rate (DCR; complete response (CR)+partial response (PR)+stable disease (SD)). Eighty studies involving mainly pretreated patients with advanced/metastatic breast (26.25%) and prostate (11.25%) cancers were retrieved. The most commonly used drug was cyclophosphamide (43%). LDM chemotherapy was frequently combined with other therapies (64.5%). Response rate (RR) and progression-free survival (PFS) were the most frequent primary end-points (24% and 19%). Mean RR was 26.03% (95% confidence interval (CI): 21.4-30.7), median PFS was 4.6months (interquartile range (IQR): 2.9-7.0) and mean DCR was 56.3% (95% CI: 50.9-61.6). RDI, DD and metronomic drug used were not associated with DCR. Grade 3/4 adverse events were rare (anaemia 7.78%, fatigue 13.4%). Thus, LDM therapy appears to be clinically beneficial and safe in a broad range of tumors. However, meta-regression analysis did not identify predictive factors of response.

Cardiovascular repair with bone marrow-derived cells

While bone marrow (BM)-derived cells have been comprehensively studied for their propitious pre-clinical results, clinical trials have shown controversial outcomes. Unlike previously acknowledged, more recent studies have now confirmed that humoral and paracrine effects are the key mechanisms for tissue regeneration and functional recovery, instead of transdifferentiation of BM-derived cells into cardiovascular tissues. The progression of the understanding of BM-derived cells has further led to exploring efficient methods to isolate and obtain, without mobilization, sufficient number of cell populations that would eventually have a higher therapeutic potential. As such, hematopoietic CD31⁺ cells, prevalent in both bone marrow and peripheral blood, have been discovered, in recent studies, to have angiogenic and vasculogenic activities and to show strong potential for therapeutic neovascularization in ischemic tissues. This article will discuss recent advancement on BM-derived cell therapy and the implication of newly discovered CD31⁺ cells.

Orally administered S-1 suppresses circulating endothelial cell counts in metastatic breast cancer patients

BACKGROUND

S-1 is an oral cytotoxic preparation that contains tegafur. Gamma-butyrolactone (GBL) is a metabolite of tegafur that is known to suppress vascular endothelial growth factor (VEGF)-mediated angiogenic activity. The aim of this study was to determine the change in circulating endothelial cell (CEC) counts, GBL levels, and angiogenesis-related factors during S-1 administration in metastatic breast cancer (MBC) patients.

METHODS

Patients with HER2-negative MBC were eligible. S-1 was administered orally twice daily in a 4 week on/2 week off cycle until disease progression or unacceptable toxicity occurred. Blood was collected on the following: days 1, 43, 85 (before each cycle of S-1 administration), days 15, 57 (1 h after S-1 administration), and day 29. The CellSearch(®) system was used to count the CECs. The gas chromatographic-mass spectrometric method was used to measure plasma GBL and 5-FU levels. Levels of VEGF were assayed by enzyme-linked immunosorbent assay.

RESULTS

A total of 18 patients were enrolled. The plasma GBL levels on days 15 and 57 were 41.3 ± 15.8 and 41.0 ± 11.2 ng/mL, respectively. The CEC levels decreased on day 15, and significantly low levels were maintained until day 85 (P = 0.002 vs day 1). The plasma VEGF levels significantly decreased on day 15 (P = 0.012 vs day 1) and had a tendency to decrease until day 57.

CONCLUSIONS

This exploratory study showed that GBL levels increased, VEGF levels decreased, and CEC levels were suppressed during S-1 administration. S-1 appears to have anti-angiogenic activity.

Photoacoustic imaging: a potential tool to detect early indicators of metastasis

The metastasis of cancer is a multistage process involving complex biological interactions and difficult to predict outcomes. Accurate assessment of the extent of metastasis is critical for clinical practice; unfortunately, medical imaging methods capable of identifying the early stages of invasion and metastasis are lacking. Photoacoustic imaging is capable of providing noninvasive, real-time imaging of significant anatomical and physiological changes. indicating the progression of cancer invasion and metastasis. Preclinically, photoacoustic methods have been used to image lymphatic anatomy, including the sentinel lymph nodes, to identify circulating tumor cells within vasculature and to detect micrometastases. Progress has begun toward the development of clinically applicable photoacoustic imaging systems to assist with the determination of cancer stage and likelihood of metastatic invasion.

Recent advances in cellular glycomic analyses

A large variety of glycans is intricately located on the cell surface, and the overall profile (the glycome, given the entire repertoire of glycoconjugate-associated sugars in cells and tissues) is believed to be crucial for the diverse roles of glycans, which are mediated by specific interactions that control cell-cell adhesion, immune response, microbial pathogenesis and other cellular events. The glycomic profile also reflects cellular alterations, such as development, differentiation and cancerous change. A glycoconjugate-based approach would therefore be expected to streamline discovery of novel cellular biomarkers. Development of such an approach has proven challenging, due to the technical difficulties associated with the analysis of various types of cellular glycomes; however, recent progress in the development of analytical methodologies and strategies has begun to clarify the cellular glycomics of various classes of glycoconjugates. This review focuses on recent advances in the technical aspects of cellular glycomic analyses of major classes of glycoconjugates, including N- and O-linked glycans, derived from glycoproteins, proteoglycans and glycosphingolipids. Articles that unveil the glycomics of various biologically important cells, including embryonic and somatic stem cells, induced pluripotent stem (iPS) cells and cancer cells, are discussed.

Progression of choroidal metastasis of ovarian serous cystoadenocarcinoma after intravitreal bevacizumab treatment

A 57-year-old woman presented to her ophthalmologist because of rapid deterioration in vision. Dilated funduscopic examination of the right eye showed an elevated, yellow-orange choroidal mass temporal to the fovea; a complete retinal detachment was present in the left eye. The patient was referred to an oncologist. Computerized tomography of the brain, thorax, abdomen, and pelvis were obtained. They revealed an 11-mm mass in the right parietal lobe, a 30-mm mass in the left temporal lobe, 23-mm mass in the right kidney, and multiple nodules in both lungs. Supported by published experience with intravitreal bevacizumab for choroidal metastasis, the patient was injected into the vitreous through the pars plana of the left eye. The tumor mass did not show signs of regression and the visual acuity was unchanged. The patient suffered from end-state complications tumor metastasis and expired one month after the invitreal injection.

Angiogenesis in neuroendocrine tumors: therapeutic applications

The considerable research efforts devoted to the understanding of the mechanisms of tumor angiogenesis have resulted in the development of targeted anti-angiogenic therapies and finally in their introduction in clinical practice. Neuroendocrine tumors (NETs), which are characterized by a high vascular supply and a strong expression of VEGF-A, one of the most potent pro-angiogenic factors, are an attractive indication for these new treatments. However, several lines of evidence show that the dense vascular networks associated with low-grade NETs are more likely to be a marker of differentiation than a marker of aggressiveness, as in other epithelial tumors. These observations form the basis for the so-called 'neuroendocrine paradox', according to which the most vascularized are the most differentiated and the less angiogenic NETs. This must be kept in mind when discussing the role of anti-angiogenic strategies in the treatment of NETs. Nevertheless, several targeted therapies, with direct or indirect anti-angiogenic properties, including anti-VEGF antibodies, tyrosine kinase inhibitors (sunitinib) and mTOR inhibitors (everolimus), have recently proven to be of clinical benefit. In addition, some drugs already used in NET treatment, such as somatostatin analogues and interferon-α, may also have anti-angiogenic properties. The main challenges for the next future are to validate biomarkers for the selection of patients and the prediction of their response to refine the indications of anti-angiogenic targeted therapies and to overcome the mechanisms of resistance, which explain the limited duration of action of most of these treatments.

Role of the VEGF/VEGFR axis in cancer biology and therapy

New vessel formation (angiogenesis) is an essential physiological process for embryologic development, normal growth, and tissue repair. Angiogenesis is tightly regulated at the molecular level; however, this process is dysregulated in several pathological conditions such as cancer. The imbalance between pro- and antiangiogenic signaling molecules within tumors creates an abnormal vascular network that is characterized by dilated, tortuous, and leaky vessels. The pathophysiological consequences of these vascular abnormalities include temporal and spatial heterogeneity in tumor blood flow, oxygenation, and increased tumor interstitial fluid pressure. The resultant microenvironment deeply impacts on tumor progression, and also leads to a reduction in therapy efficacy. The discovery of vascular endothelial growth factor (VEGF) as a major driver of tumor angiogenesis has led to efforts to develop novel therapeutics aimed at inhibiting its activity. Anti-VEGF therapy has become an important option for the management of several human malignancies; however, a significant number of patients do not respond to anti-VEGF therapy when used either as single agent or in combination with chemotherapy. In addition, the benefit of antiangiogenic therapy is relatively short lived and the majority of patients relapse and progress. An increasing amount of reports suggest several potential mechanisms of resistance to antiangiogenic therapy including, but not limited to, tumor hypoxia. This chapter discusses the role of the VEGF axis in tumor biology and highlights the clinical application of anti-VEGF therapies elaborating on pitfalls and strategies to improve clinical outcome.

Prospective study of thrombospondin-1 mimetic peptides, ABT-510 and ABT-898, in dogs with soft tissue sarcoma

BACKGROUND

Exposure to anti-angiogenic thrombospondin-1 (TSP-1) mimetic peptides (MPs) has resulted in sporadic anti-tumor activity in humans and dogs.

HYPOTHESIS

Novel TSP-1 MPs formulations will be safe, tolerated, and clinically active in soft tissue sarcoma (STS) in dogs.

ANIMALS

Sixty-two client-owned dogs with measurable STS were enrolled, excluding hemangiosarcoma.

METHODS

A prospective, single agent, multicenter, open-label study assessing ABT-510 bolus, ABT-898 bolus, or ABT-898 depot formulations of TSP-1 in dogs. Endpoints included tolerability, antitumor activity, and the assessment of ability of clinical covariates and circulating endothelial cells (CEC) concentration to predict tumor response.

RESULTS

Two non-dose-limiting toxicoses possibly attributed to treatment were observed (keratitis and osteoarthritis). Antitumor activity (10/44 = 23% responses) was observed in study subjects who received treatment for >28 days (n = 44) including both partial (7) and minimal responses (3). Responses were disproportionately seen in dogs receiving ABT-898 formulations (9/28 = 32%) versus those receiving ABT-510 (1/16 = 6%; P < .045). Disease stabilization for >84 days was also documented (8/44 = 18%). Slow rates of tumor progression before study entry correlated with anti-tumor activity in treated dogs, whereas no significant association was found between changes in total CEC concentration and tumor response (P = .28) or time to progression (P = .42).

CONCLUSIONS AND CLINICAL IMPORTANCE

Safely achieved antitumor activity was documented with TSP-1 MPs in dogs with STS. The most notable activity was achieved with the ABT-898 formulations.

Forty-year journey of angiogenesis translational research

Forty years ago, Judah Folkman predicted that tumor growth is dependent on angiogenesis and that inhibiting this process might be a new strategy for cancer therapy. This hypothesis formed the foundation of a new field of research that represents an excellent example of how a groundbreaking scientific discovery can be translated to yield benefits for patients. Today, antiangiogenic drugs are used to treat human cancers and retinal vascular diseases. Here, we guide readers through 40 years of angiogenesis research and discuss challenges of antiangiogenic therapy.

Discrimination between circulating endothelial cells and blood cell populations with overlapping phenotype reveals distinct regulation and predictive potential in cancer therapy

BACKGROUND

Circulating endothelial cells (CECs) have been proposed to predict patient response to antiangiogenic cancer therapy. However, contradictory reports and inconsistency in the phenotypic identification of CECs have led us to compare three cell populations with partially overlapping phenotype in cancer patients receiving chemotherapy and the antiangiogenic agent bevacizumab.

METHODS

Patients (n = 20) with locally advanced pancreatic cancer were monitored during 16 weeks of neoadjuvant treatment with gemcitabine and bevacizumab. Detection of circulating cell populations was based on the marker combination CD45, CD31, and CD146; levels of viable and dead (7-aminoactinomycin D-positive) cells were evaluated by flow cytometry in 2-week intervals.

RESULTS

We were able to discriminate and concomitantly monitor three cell populations elevated in cancer patients. Whereas CECs were defined as CD45(-) CD31(+) CD146(+), the distinct populations of CD45(-) CD31(-) CD146(+) and CD45(-) CD31(high) CD146(-) cells were partly positive for CD3 and CD41, respectively. CECs and CD45(-) CD31(-) CD146(+) cells increased during therapy; the rise in dead cells was positively correlated with patient response or survival. Conversely, CD45(-) CD31(high) CD146(-) cells decreased in neoadjuvant treatment. A highly significant correlation was established for improved patient response and a minor decrease in viable cell counts.

CONCLUSIONS

Flow cytometric CEC analysis based on CD45, CD31, and CD146 requires careful discrimination between blood cell populations with overlapping phenotype showing hallmarks of activated T cells and large platelets. However, these three cell populations show distinct regulation during cancer therapy, and their concomitant analysis may offer extended prognostic and predictive information.

Circulating endothelial cells and their apoptotic fraction are mutually independent predictive biomarkers in Bevacizumab-based treatment for advanced colorectal cancer

BACKGROUND

Bevacizumab has shown consistent clinical efficacy in metastatic colorectal cancer (mCRC), but some patients respond better than others. Thus, it is crucial to identify biomarkers that permit the recognition of potentially responsive subjects and to spare toxicity in those who are unlikely benefit from treatment.

METHODS

In 24 mCRC patients undergoing Bevacizumab-based first-line treatment, we assessed by multiparameter flow cytometry changes in circulating endothelial cell (CEC) number, their apoptotic fraction (APO-CEC) and their mutual relationship. Data were compared with those from a group of 21 healthy subjects.

RESULTS

CECs and APO-CECs were higher in patients versus controls (p = 0.01 and p > 0.05, respectively). The increase in CECs at the 3rd cycle in complete response (CR) patients was statistically significant (p = 0.048). A better progression-free survival was evidenced in patients that showed an increase in CECs at the 6th cycle (p = 0.009). Regarding the changes in CECs and APO-CECs, a strong correlation was evidenced, at baseline, both in the global population (0.002; r: 0.53) and in the CR subgroup (p: 0.02; r: 0.77). In the partial response + stable and progression disease (SD + PD) subgroup, this correlation was highly significant at the 6th cycle (p: 0.001; r: 0.83).

CONCLUSIONS

We confirmed the predictive role of an increase in CECs in mCRC patients treated with Bevacizumab-based therapy and showed that modifications in CECs and APO-CECs are independent factors. This underlines the relevance of a simultaneous quantitative and functional evaluation of these biomarkers in view of their possible diagnostic utility.

Clinical value of circulating endothelial cell detection in oncology

Given the importance of tumor vasculature in tumor biology and as a target for treatment, there is an increasing need for biomarkers that reflect effects impacting tumor vasculature accurately. Circulating endothelial cells (CECs) increase in number as a result of vascular damage in cancer and several other diseases. CEC count constitutes a promising tool for monitoring disease activity with potential to assess prognosis and response to treatment. Here, we address the current state-of-the-art of CEC enumeration as a biomarker in clinical oncology. We focus on technical issues concerning CEC detection, review results from clinical studies and explore future potential applications.

A phase I, dose-escalation study of TB-403, a monoclonal antibody directed against PlGF, in patients with advanced solid tumours

Background:

TB-403 (RO 5323441), a humanised monoclonal antibody, is a novel antiangiogenesis agent directed against placental growth factor. The safety, pharmacokinetics (PK), and antitumour activity of TB-403 were assessed in a phase I, dose-escalation study in patients with advanced solid tumours.

Methods:

Patients in sequential dose groups received either weekly doses of 1.25, 5.0, or 10 mg kg⁻¹ or doses of 20 or 30 mg kg⁻¹ every third week.

Results:

Twenty-three patients were enrolled and received TB-403. The most common adverse events (AEs) were fatigue, constipation, pyrexia, dyspnoea, and nausea. One serious AE, a lung embolus in a patient with non-small cell lung cancer treated with 10 mg kg⁻¹ weekly, was deemed possibly related to TB-403. No dose-limiting toxicities were observed, and a maximum-tolerated dose was not reached. The PK parameters were dose linear and the terminal half-life values ranged from 9 to 14 days. Six patients exhibited stable disease for at least 8 weeks. Two patients, (oesophageal squamous cell carcinoma and pancreatic adenocarcinoma) both treated with 5 mg kg⁻¹ weekly, remained stable for 12 months.

Conclusion:

TB-403 treatment in this patient population is well tolerated, with a safety profile distinct from that of vascular endothelial growth factor-axis inhibitors.

Anti-VEGF and beyond: shaping a new generation of anti-angiogenic therapies for cancer

The anti-angiogenic class of drugs is one of the few where representatives have gained international approval for clinical use in oncology during the past decade. Most of the biological and clinical activity of the currently available generation of anti-angiogenic drugs targets vascular endothelial growth factor (VEGF) and its related pathways. However, the clinical benefits associated with the use of these drugs have, so far, been limited. There is, therefore, an unmet need for biomarkers that can be used to identify patients who are most likely to benefit therapeutically and also to predict the best schedule and dosage for these drugs. Here, we discuss some of the emerging new combination strategies involving the approved anti-angiogenic drugs, some of the emerging targets associated with neoplastic angiogenesis and some novel agents used as a paradigm of the next generation of anti-angiogenic drugs.

AIDS-Kaposi Sarcoma and Classic Kaposi Sarcoma: are different ultrasound patterns related to different variants?

BACKGROUND

Kaposi Sarcoma (KS) is a malignancy of endothelial skin cells with multifocal localization on the skin, lymph nodes and visceral organs. Although all clinical variants are associated with HHV-8 infection, specific differences in the clinical onset and in the natural history of AIDS-KS and Classic-KS have been described. The present randomised prospective-observational study aimed to investigate whether the ultrasound pattern and color Doppler flow imaging of vascularisation of skin lesions of patients with Classic KS (CKS) or AIDS-KS could provide useful information to the evaluation of clinical activity of the disease.

METHODS

Cutaneous lesions of 24 patients with histologically confirmed KS were investigated using very high frequency ultrasound probes; 16 patients had CKS and 8 had AIDS-KS. HHV-8 infection was confirmed in all patients by investigating the specific humoral response to viral antigens. Immunological and virological parameters were also assessed to monitor HIV or HHV-8 viral infection. For each patient, a target skin lesion was selected on the basis of size (diameter from 0.4 to 2 cm). Each lesion was analyzed in terms of size, depth and color Doppler pattern.

RESULTS

The B-mode ultrasound patterns of skin lesions did not differ when comparing CKS patients to AIDS-KS patients, whereas the color Doppler signal, which is associated with vascular activity, was detected in the KS lesions of 6/8 AIDS-KS patients (75.0%) and in 2/16 CKS (16,7%); the latter two patients showed a clinically progressive and extensive disease stage (IV B).

CONCLUSIONS

Our preliminary results suggest that small cutaneous KS lesions - in both CKS and AIDS-KS patients- display similar B-mode ultrasound patterns ( hypoechoic, well defined, superficial lesions). However, the color Doppler signal, which is associated with endothelial activity and angiogenesis, which play a substantial role in KS progression, could constitute a useful tool for evaluating disease activity.

Multi-parametric assessment of the anti-angiogenic effects of liposomal glucocorticoids

Inflammation plays a prominent role in tumor growth. Anti-inflammatory drugs have therefore been proposed as anti-cancer therapeutics. In this study, we determined the anti-angiogenic activity of a single dose of liposomal prednisolone phosphate (PLP-L), by monitoring tumor vascular function and viability over a period of one week. C57BL/6 mice were inoculated subcutaneously with B16F10 melanoma cells. Six animals were PLP-L-treated and six served as control. Tumor tissue and vascular function were probed using MRI before and at three timepoints after treatment. DCE-MRI was used to determine K(trans), v(e), time-to-peak, initial slope and the fraction of non-enhancing pixels, complemented with immunohistochemistry. The apparent diffusion coefficient (ADC), T(2) and tumor size were assessed with MRI as well. PLP-L treatment resulted in smaller tumors and caused a significant drop in K(trans) 48 h post-treatment, which was maintained until one week after drug administration. However, this effect was not sufficient to significantly distinguish treated from non-treated animals. The therapy did not affect tumor tissue viability but did prevent the ADC decrease observed in the control group. No evidence for PLP-L-induced tumor vessel normalization was found on histology. Treatment with PLP-L altered tumor vascular function. This effect did not fully explain the tumor growth inhibition, suggesting a broader spectrum of PLP-L activities.

Prolongation of cardiac allograft survival by a novel population of autologous CD117+ bone marrow-derived progenitor cells

Autologous CD117(+) progenitor cells (PC) have been successfully utilized in myocardial infarction and ischemic injury, potentially through the replacement/repair of damaged vascular endothelium. To date, such cells have not been used to enhance solid organ transplant outcome. In this study, we determined whether autologous bone marrow-derived CD117(+) PC could benefit cardiac allograft survival, possibly by replacing donor vascular cells. Autologous, positively selected CD117(+) PC were administered posttransplantation and allografts were assessed for acute rejection. Although significant generation of recipient vascular cell chimerism was not observed, transferred PC disseminated both to the allograft and to peripheral lymphoid tissues and facilitated a significant, dose-dependent prolongation of allograft survival. While CD117(+) PC dramatically inhibited alloreactive T cell proliferation in vitro, this property did not differ from nonprotective CD117(-) bone marrow populations. In vivo, CD117(+) PC did not significantly inhibit T cell alloreactivity or increase peripheral regulatory T cell numbers. Thus, rather than inhibiting adaptive immunity to the allograft, CD117(+) PC may play a cytoprotective role in prolonging graft survival. Importantly, autologous CD117(+) PC appear to be distinct from bone marrow-derived mesenchymal stem cells (MSC) previously used to prolong allograft survival. As such, autologous CD117(+) PC represent a novel cellular therapy for promoting allograft survival.

RGD modified albumin nanospheres for tumour vasculature targeting

Objectives

Cyclic arginine-glycine-aspartic acid (RGD) peptide-anchored sterically stabilized albumin nanospheres (RGD-SN) have been investigated for the selective and preferential presentation of carrier contents at angiogenic endothelial cells overexpressing avb3 integrins on and around tumour tissue. Their targetabilty was assessed.

Methods

Albumin nanospheres were formulated, conjugated with RGD/RAD peptide and characterized on the basis of size and size distribution. The control Arginine-Alanine-Aspartic acid (RAD) peptide-anchored sterically stabilized nanospheres (RAD-SN) and nanosphere with 5 mol% PEG (SN) without peptide conjugate were used for comparison with RGD-SN for in vitro cell binding, in vivo organ distribution and tumor angiogenesis studies.

Key findings

The average size of all nanospheres prepared was approximately 100 nm and maximum drug entrapment was 67.2 ± 5.2%. In-vitro endothelial cell binding of nanospheres exhibited 8-fold higher binding of RGD-SN to human umbilical vein endothelial cells in comparison with the SN and RAD-SN. RGD peptide-anchored nanospheres were significantly (P ≤ 0.01) effective in the prevention of lung metastasis, angiogenesis and in effective regression of tumours compared with free fluorouracil, SN and RAD-SN. Results indicated that cyclic RGD peptide-anchored sterically stabilized nanospheres bearing fluorouracil were significantly (P ≤ 0.01) active against primary tumour and metastasis than the nontargeted sterically stabilized nanospheres and free drug.

Conclusions

Cyclic RGD peptide-anchored sterically stabilized nanospheres appears promising for targeted cancer chemotherapeutics.

Early alpha-fetoprotein response predicts treatment efficacy of antiangiogenic systemic therapy in patients with advanced hepatocellular carcinoma

BACKGROUND

Antiangiogenic therapy has become the most important treatment modality for patients with advanced hepatocellular carcinoma (HCC). In this study, the authors investigated levels of alpha-fetoprotein (AFP) as a potential biomarker for treatment efficacy of antiangiogenic therapy.

METHODS

Patients with advanced HCC who had been enrolled in 3 prospective phase 2 clinical trials that evaluated either sorafenib, bevacizumab, or thalidomide in combination with a potentially antiangiogenic, metronomic, oral 5-fluoropyrimidine as first-line systemic therapy were included. An early AFP response was defined as a decline >20% from baseline after 2 to 4 weeks of treatment. AFP response was analyzed for its association with treatment efficacy and survival outcome.

RESULTS

Seventy-two patients were included for early AFP response evaluation, and 12 of those patients (17%) were classified as early AFP responders. Early AFP responders, compared with nonresponders, had a significantly improved overall response rate (33% vs 8%; P=.037) and a significantly improved disease control rate (83% vs 35%; P=.002), which was defined as the percentage of patients who had an objective response plus stable disease for a minimum of 8 weeks. AFP responders, compared with nonresponders, also had longer median progression-free survival (PFS) (7.5 months vs 1.9 months; P=.001) and longer median overall survival (OS) (15.3 months vs 4.1 months; P=.019). In a multivariate analysis, AFP response remained a significant independent predictor of better PFS and OS.

CONCLUSIONS

The current results indicated that an early AFP response is a useful surrogate marker to predict treatment response and prognosis in patients with advanced HCC who receive antiangiogenic therapy.

Liposomes modified with YIGSR peptide for tumor targeting

YIGSR peptide anchored sterically stabilized liposomes (YIGSR-SL) were investigated for selective and preferential presentation of carrier contents at angiogenic endothelial cells overexpressing laminin receptors on and around tumor tissue and thus for assessing their targetabilty. In vitro endothelial cell binding of liposomes exhibited 7-fold higher binding of YIGSR-SL to HUVEC in comparison to the nontargeted sterically stabilized liposomes (SL). Spontaneous lung metastasis and angiogenesis assays show that YIGSR peptide anchored liposomes are significantly (P <or= 0.01) effective in the prevention of lung metastasis and angiogenesis compared to free 5-fluorouracil (5-FU) and SL. YIGSR-SL was very effective in regression of tumors in BALB/c mice bearing B16F10 melanoma cells. Results indicate that YIGSR peptide anchored sterically stabilized liposomes bearing 5-FU are significantly (P <or= 0.01) active against primary tumor and metastasis than the SL and free drug. Thus, YIGSR peptide anchored sterically stabilized liposomes hold potential of targeted cancer chemotherapeutics.

Molecular targeted therapy for advanced hepatocellular carcinoma: current status and future perspectives

Sorafenib, a multikinase inhibitor targeting vascular endothelial growth factor (VEGF)-mediated angiogenesis, is the first drug found to prolong survival of patients with advanced hepatocellular carcinoma (HCC). This advance has shifted the paradigm of systemic treatment for HCC toward molecular targeted therapy (MTT). However, the disease-stabilizing effect of VEGF signaling-targeted MTT normally lasts only for a few months, suggesting a rapid emergence of resistance in the majority of patients. To overcome the resistance to VEGF signaling-targeted MTT, strategies incorporating inhibition of either compensatory pro-angiogenic pathways or recruitment of bone marrow-derived circulating endothelial progenitors, as well as suppression of other oncogenic pathways, are currently being investigated. The combination of multiple molecular targeted agents or the use of multi-target agents may enhance the efficacy at the expense of increased toxicities. To facilitate the development of MTT for HCC, current methodologies for pharmacodynamic assessment, patient selection and target identification need to be improved. Patient selection according to the individual molecular signature of the tumor and correlative biomarker studies are encouraged while planning a clinical trial of novel MTT.

Phase II study of combining sorafenib with metronomic tegafur/uracil for advanced hepatocellular carcinoma

BACKGROUND & AIMS

Sorafenib, a multi-kinase inhibitor with anti-angiogenic activity, was recently approved for the treatment of advanced hepatocellular carcinoma (HCC). Metronomic chemotherapy using tegafur/uracil (4:1 molar ratio), an oral fluoropyrimidine, has been shown to enhance the anti-tumor effect of anti-angiogenic agents in preclinical models. This phase II study evaluated the efficacy and safety of combining metronomic tegafur/uracil with sorafenib in patients with advanced HCC.

METHODS

Patients with histologically- or cytologically-proven HCC and Child-Pugh class A liver function were treated with sorafenib (400mg twice daily) and tegafur/uracil (125 mg/m(2) based on tegafur twice daily) continuously as first-line therapy for metastatic or locally advanced disease that could not be treated by loco-regional therapies. The primary endpoint was progression-free survival (PFS).

RESULTS

The study enrolled 53 patients. Thirty-eight patients (72%) were hepatitis B surface antigen-positive. The median PFS was 3.7 months (95% C.I., 1.9-5.5) and the median overall survival was 7.4 months (95% C.I., 3.4-11.4). According to RECIST criteria, 4 patients (8%) had a partial response and 26 patients (49%) had a stable disease. Major grade 3/4 toxicities included fatigue (15%), abnormal liver function (13%), elevated serum lipase (10%) hand-foot skin reaction (HFSR) (9%), and bleeding (8%). HFSR was the major adverse event resulting in dose reduction (19%) or treatment delay (21%).

CONCLUSIONS

Metronomic chemotherapy with tegafur/uracil can be safely combined with sorafenib and shows preliminary activity to improve the efficacy of sorafenib in advanced HCC patients.

Optimizing the delivery of cancer drugs that block angiogenesis

Drugs that block angiogenesis are important components of first-line therapies for a number of human cancers. However, some of these agents have undesirable effects on the patient. Optimal delivery systems must be developed to maximize clinical benefits and minimize adverse effects in cancer patients. In this Perspective, we discuss these drug-related issues and propose ways to optimize antiangiogenic therapy by the development of new drug delivery systems.

Metronomic chemotherapy: new rationale for new directions

Tumor angiogenesis is recognized as a major therapeutic target in the fight against cancer. The key involvement of angiogenesis in tumor growth and metastasis has started to redefine chemotherapy and new protocols have emerged. Metronomic chemotherapy, which is intended to prevent tumor angiogenesis, is based on more frequent and low-dose drug administrations compared with conventional chemotherapy. The potential of metronomic chemotherapy was revealed in animal models a decade ago and the efficacy of this approach has been confirmed in the clinic. In the past 5 years, multiple clinical trials have investigated the safety and efficacy of metronomic chemotherapy in a variety of human cancers. While the results have been variable, clinical studies have shown that these new treatment protocols represent an interesting alternative for either primary systemic therapy or maintenance therapy. We review the latest clinical trials of metronomic chemotherapy in adult and pediatric cancer patients. Accumulating evidence suggests that the efficacy of such treatment may not only rely on anti-angiogenic activity. Potential new mechanisms of action, such as restoration of anticancer immune response and induction of tumor dormancy are discussed. Finally, we highlight the research efforts that need to be made to facilitate the optimal development of metronomic chemotherapy.

Blood-based biomarkers for the optimization of anti-angiogenic therapies

The dependence of tumor growth and metastasis on blood vessels makes tumor angiogenesis a rational target for therapy. Strategies have been pursued to inhibit neovascularization and to destroy existing tumor vessels, or both. These include direct targeting of endothelial cells, and indirect targeting by inhibiting the release of proangiogenic growth factors by cancer or stromal cells. Many patients benefit from antiangiogenic therapies; thus, development of noninvasive biomarkers of disease response and relapse is a crucial objective to aid in their management. A number of non-invasive tools are described with their potential benefits and limitations. We review currently available candidate biomarkers of anti-angiogenic agent effect. Including these markers into clinical trials may provide insight into appropriate dosing for desired biological effects, appropriate timing of additional therapy, and prediction of individual response. This has important consequences for the clinical use of angiogenesis inhibitors and for drug discovery, not only for optimizing the treatment of cancer, but possibly also for developing therapeutic approaches for various other diseases.

Circulating endothelial cells and endothelial progenitors as predictive markers of clinical response to bevacizumab-based first-line treatment in advanced colorectal cancer patients

BACKGROUND

Despite the consistent clinical results demonstrated by studies on anti-angiogenic drugs targeted against the vascular endothelial growth factor in metastatic colorectal cancer (mCRC) patients, no specific direct/indirect biomarker of their efficacy has been validated. In this field, circulating endothelial cells (CECs) and endothelial progenitor cells (CEPs) have recently been proposed as noninvasive biomarkers.

PATIENTS AND METHODS

The absolute numbers of CEPs, total CECs (tCECs) and their resting (rCECs) and activated subsets were evaluated by multiparameter flow cytometry in 40 mCRC patients at baseline and before the administration of the third and sixth course of a bevacizumab-based first-line treatment. Fifty healthy subjects were utilized as control.

RESULTS

The overall response rate was 80%, overall clinical benefit was 90% and median progression-free survival (PFS) was 13.8 months. In our patients, tCECs and rCECs were significantly increased compared with healthy subjects. The patients who achieved a radiological response showed, at baseline, a significant decrease of rCECs and a trend in decrease of tCECs in comparison with patients not achieving response. Finally, a baseline absolute number of tCEC and rCEC <40 cells/ml was evidenced in patients with a longer PFS. No correlation was found regarding CEP.

CONCLUSIONS

Our study suggests significant correlations between both tCEC and rCEC baseline levels and the antitumor efficacy of a bevacizumab-based combination therapy in mCRC patients, thus confirming that these biomarkers could be used in the clinical setting as an early predictor of tumor response.

Biomarkers for angiogenesis and antiangiogenic drugs in clinical oncology

AIMS

The clinical use of anti-angiogenic drugs, alone or in combination with other drugs, is increasing in medical oncology. However, identifying the best suited drug and the optimal dosage and schedule for treatment of patients remain challenging.

METHODS AND RESULTS

We reviewed data about surrogate biomarkers of angiogenesis and anti-angiogenic drug activity currently available in the literature. Circulating endothelial cells (CECs) and circulating endothelial progenitors (CEPs) have been found to have some predictive potential in some clinical trials involving advanced breast cancer patients. Molecular surrogate markers, on the other hand, are more scanty at the present time, because the identification of truly endothelial-cell-restricted genes and/or antigens has been so far more elusive.

CONCLUSION

The search and validation of new biomarkers for angiogenesis and anti-angiogenic drug activity have many biological, technical and clinical facets which render this task particularly complex. An accurate planning of biomarker search and validation throughout future clinical studies is highly warranted.

Plasma cytokine and angiogenic factor profiling identifies markers associated with tumor shrinkage in early-stage non-small cell lung cancer patients treated with pazopanib

There is an unmet need for pharmacodynamic and predictive biomarkers for antiangiogenic agents. Recent studies have shown that soluble vascular endothelial growth factor receptor 2 (sVEGFR2), VEGF, and several other soluble factors may be modulated by VEGF pathway inhibitors. We conducted a broad profiling of cytokine and angiogenic factors (CAF) to investigate the relationship between baseline CAF levels, CAF changes during treatment, and tumor shrinkage in early-stage non-small cell lung cancer (NSCLC) patients treated with pazopanib, an oral angiogenesis inhibitor targeting VEGFR, platelet-derived growth factor receptor, and c-kit. Plasma samples were collected before treatment and on the last day of therapy from 33 patients with early-stage NSCLC participating in a single-arm phase II trial. Levels of 31 CAFs were measured by suspension bead multiplex assays or ELISA and correlated with change in tumor volume. Pazopanib therapy was associated with significant changes of eight CAFs; sVEGFR2 showed the largest decrease, whereas placental growth factor underwent the largest increase. Increases were also observed in stromal cell-derived factor-1alpha, IP-10, cutaneous T-cell-attracting chemokine, monokine induced by IFN-gamma, tumor necrosis factor-related apoptosis-inducing ligand, and IFN-alpha. Posttreatment changes in plasma sVEGFR2 and interleukin (IL)-4 significantly correlated with tumor shrinkage. Baseline levels of 11 CAFs significantly correlated with tumor shrinkage, with IL-12 showing the strongest association. Using multivariate classification, a baseline CAF signature consisting of hepatocyte growth factor and IL-12 was associated with tumor response to pazopanib and identified responding patients with 81% accuracy. These data suggest that CAF profiling may be useful for identifying patients likely to benefit from pazopanib, and merit further investigation in clinical trials.

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.

Expression sites of colligin 2 in glioma blood vessels

In a previous study using state-of-the-art proteomic techniques, we identified colligin 2 (HSP47) as a glioma blood vessel-specific protein. In the present study we precisely localized the expression of colligin 2 in the blood vessels of diffusely infiltrating gliomas and relate the expression to the distinct cellular components of the vessels by using multiple immunolabeling and confocal microscopy. We grouped the glioma blood vessels into morphological categories ranging from normal looking capillaries to vessels with hypertrophic and sclerotic changes. The expression patterns of various markers of endothelial and pericytic differentiation were correlated with the position of the cells in the vessels and the expression of colligin 2. We found that colligin 2 is expressed in all categories of glioma blood vessels in cells with endothelial and pericytic lineage. Expression of colligin 2 was also found in cells scattered around blood vessels and in few glial fibrillary acidic protein-positive cells within the blood vessels. There is overlap in the expression of colligin 2 and the collagens type I and IV for which colligin 2 is a chaperon. We conclude that colligin 2 is expressed in all cellular components of glioma blood vessels and may serve as a general marker for active angiogenesis.