The role of vascular endothelial growth factor in pathological angiogenesis

Synergistic antitumor activity of sorafenib in combination with epidermal growth factor receptor inhibitors in colorectal and lung cancer cells

PURPOSE

Cancer cell survival, invasion, and metastasis depend on cancer cell proliferation and on tumor-induced angiogenesis. We evaluated the efficacy of the combination of sorafenib and erlotinib or cetuximab.

EXPERIMENTAL DESIGN

Sorafenib, erlotinib, and cetuximab, alone or in combination, were tested in vitro in a panel of non-small cell lung cancer (NSCLC) and colorectal cancer cell lines and in vivo in H1299 tumor xenografts.

RESULTS

Epidermal growth factor receptor (EGFR) ligand mRNAs were expressed in all NSCLC and colorectal cancer cell lines with variable levels ranging from 0.4- to 8.1-fold as compared with GEO colorectal cancer cells. Lung cancer cells had the highest levels of vascular endothelial growth factors (VEGF) A, B, and C, and of VEGF receptors as compared with colorectal cancer cells. Combined treatments of sorafenib with erlotinib or cetuximab produced combination index values between 0.02 and 0.5, suggesting a significant synergistic activity to inhibit soft agar colony formation in all cancer cell lines, which was accompanied by a marked blockade in mitogen-activated protein kinase and AKT signals. The in vitro migration of H1299 cells, which expressed high levels of both VEGF ligands and receptors, was inhibited by treatment with sorafenib, and this effect was significantly increased by the combination with anti-EGFR drugs. In nude mice bearing established human H1299 xenografts, treatment with the combination of sorafenib and erlotinib or cetuximab caused a significant tumor growth delay resulting in 70 to 90 days increase in mice median overall survival as compared with single-agent sorafenib treatment.

CONCLUSIONS

Combination treatment with sorafenib and erlotinib or cetuximab has synergistic antitumor effects in human colorectal and lung cancer cells.

Gold nanoparticles: opportunities and challenges in nanomedicine

IMPORTANCE OF THE FIELD

Site-specific drug delivery is an important area of research that is anticipated to increase the efficacy of the drug and reduce potential side effects. Owing to this, substantial work has been done developing non-invasive and targeted tumor treatment with nanoscale metallic particles.

AREAS COVERED IN THIS REVIEW

This review focuses on the work done in the last few years developing gold nanoparticles as cancer therapeutics and diagnostic agents. However, there are challenges in using gold nanoparticles as drug delivery systems, such as biodistribution, pharmacokinetics and possible toxicity. Approaches to limit these issues are proposed.

WHAT THE READER WILL GAIN

Different approaches from several different disciplines are discussed. Potential clinical applications of these engineered nanoparticles are also presented.

TAKE HOME MESSAGE

As a result of their unique size-dependent physicochemical and optical properties, adaptability, subcellular size and biocompatibility, these nanosized carriers offer a suitable means of transporting small molecules as well as biomacromolecules to diseased cells/tissues.

A phase II study of 2-methoxyestradiol (2ME2) NanoCrystal® dispersion (NCD) in patients with taxane-refractory, metastatic castrate-resistant prostate cancer (CRPC)

PURPOSE

2ME2 (Panzem®) is a non-estrogenic derivative of estradiol with antiproliferative and antiangiogenic activity. Preclinical data support antitumor activity in prostate cancer. This trial evaluated the efficacy of 2ME2 NCD in patients with taxane-refractory, metastatic CRPC.

EXPERIMENTAL DESIGN

Patients with metastatic CRPC who had progressed on only one prior taxane-based regimen were eligible. All patients received 2ME2 NCD at 1,500 mg orally four times daily, repeated in 28 day cycles. The primary endpoint was progression-free survival at month 6, with a secondary endpoint of PSA response. An exploratory endpoint was metabolic response on FDG-PET imaging.

RESULTS

A total of 50 pts was planned. The study was terminated after 21 pts when a futility analysis showed the primary endpoint was unlikely to be reached. The median number of cycles on study was 2 (range <1 to 12). Adverse events (AE) of grade ≥3 related to the study drug occurred in 7 unique patients (33%): elevations in liver function tests, fatigue or weakness, gastrointestinal hemorrhage, and hyponatremia. Paired FDG-PET scans were obtained for 11 pts. No metabolic responses were observed.

CONCLUSIONS

2ME2 NCD did not appear to have clinically significant activity in this study. 2ME2 NCD was well-tolerated and showed some evidence of biologic activity. Given the aggressive biology in this taxane-refractory population, the potential benefit from a cytostatic agent like 2ME2 might better be realized in the pre-chemotherapy (or rising PSA only) stage of CRPC.

Studies on glyphosate-induced carcinogenicity in mouse skin: a proteomic approach

Glyphosate is a widely used broad spectrum herbicide, reported to induce various toxic effects in non-target species, but its carcinogenic potential is still unknown. Here we showed the carcinogenic effects of glyphosate using 2-stage mouse skin carcinogenesis model and proteomic analysis. Carcinogenicity study revealed that glyphosate has tumor promoting activity. Proteomic analysis using 2-dimensional gel electrophoresis and mass spectrometry showed that 22 spots were differentially expressed (>2 fold) on glyphosate, 7, 12-dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) application over untreated control. Among them, 9 proteins (translation elongation factor eEF-1 alpha chain, carbonic anhydrase III, annexin II, calcyclin, fab fragment anti-VEGF antibody, peroxiredoxin-2, superoxide dismutase [Cu-Zn], stefin A3, and calgranulin-B) were common and showed similar expression pattern in glyphosate and TPA-treated mouse skin. These proteins are known to be involved in several key processes like apoptosis and growth-inhibition, anti-oxidant responses, etc. The up-regulation of calcyclin, calgranulin-B and down-regulation of superoxide dismutase [Cu-Zn] was further confirmed by immunoblotting, indicating that these proteins can be good candidate biomarkers for skin carcinogenesis induced by glyphosate. Altogether, these results suggested that glyphosate has tumor promoting potential in skin carcinogenesis and its mechanism seems to be similar to TPA.

Effects of epidermal growth factor and/or nerve growth factor on Malassez's epithelial rest cells in vitro: expression of mRNA for osteopontin, bone morphogenetic protein 2 and vascular endothelial growth factor

BACKGROUND AND OBJECTIVE

Malassez's epithelial rest (MER) cells are involved in the maintenance and homeostasis of the periodontal ligament (PDL). The purpose of this study was to determine the effects of epidermal growth factor (EGF) and/or nerve growth factor (NGF) in vitro on these functions of MER cells.

MATERIAL AND METHODS

MER cells from porcine PDL were incubated for 3 or 9 h after the addition of EGF and/or NGF to final concentrations of 10 ng/mL. Cells cultured without those growth factors were used as controls. The expression of mRNA for osteopontin, bone morphogenetic protein 2 (BMP-2) and vascular endothelial growth factor (VEGF) was analyzed using quantitative RT-PCR.

RESULTS

There was a decrease in the expression of osteopontin mRNA by MER cells treated for 9 h with NGF and the level of mRNA expressed was lower than that of the control and EGF-treated groups. The expression of BMP-2 mRNA by MER cells treated with NGF for 9 h also decreased, and was lower than that of the control and EGF-treated groups. The expression of VEGF mRNA by MER cells treated with EGF for 3 or 9 h was higher than in the control and NGF-treated groups. The expression of VEGF mRNA was lower in MER cells treated with NGF for 3 and 9 h than in the control and EGF-treated groups, and decreased from 3 to 9 h of treatment. EGF stimulated MER cells to secrete VEGF, which suggests that EGF plays an important role in maintaining the homeostasis of the PDL. NGF acts on MER cells to inhibit calcification in the PDL. Furthermore, in the EGF+NGF-treated MER cells, expression of mRNA for BMP-2 and VEGF was similar to that of the NGF-treated group, but cell proliferation and expression of osteopontin mRNA were similar to that of the EGF-treated group.

CONCLUSION

EGF and NGF play important roles in maintaining the PDL.

Phase 1b study of motesanib, an oral angiogenesis inhibitor, in combination with carboplatin/paclitaxel and/or panitumumab for the treatment of advanced non-small cell lung cancer

PURPOSE

Motesanib is a small-molecule antagonist of vascular endothelial growth factor receptor 1, 2, and 3, platelet-derived growth factor receptor, and Kit. This phase 1b study assessed the safety, maximum tolerated dose (MTD), and pharmacokinetics, and explored the objective response of motesanib plus carboplatin/paclitaxel and/or the fully human anti-epidermal growth factor receptor monoclonal antibody panitumumab in advanced non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Patients with unresectable NSCLC received sequentially escalating doses of motesanib [50, 125 mg once daily; 75 mg twice daily] orally continuously plus carboplatin/paclitaxel (arm A; first line) or panitumumab (arm B; first and second line) once every 21-day cycle or 125 mg once daily plus carboplatin/paclitaxel and panitumumab (arm C; first line).

RESULTS

Forty-five patients received motesanib. Three dose-limiting toxicities occurred: grade 4 pulmonary embolism (n = 1; arm A, 50 mg once daily) and grade 3 deep vein thrombosis (n = 2; arm A, 125 mg once daily; arm C). The MTD was 125 mg once daily. Common motesanib-related adverse events were fatigue (60% of patients), diarrhea (53%), hypertension, (38%), anorexia (27%), and nausea (22%). Three cases of cholecystitis occurred but only in the 75-mg twice-daily schedule, which was subsequently discontinued. At 125 mg once daily, motesanib pharmacokinetics were not markedly changed with carboplatin/paclitaxel coadministration; however, exposure to paclitaxel was moderately increased. The objective response rates were 17%, 0%, and 17% in arms A, B, and C, respectively.

CONCLUSIONS

Treatment with motesanib was tolerable when combined with carboplatin/paclitaxel and/or panitumumab, with little effect on motesanib pharmacokinetics at the 125-mg once daily dose level. This dose is being investigated in an ongoing phase 3 study in NSCLC.

Angiogenesis and ovarian cancer

Ovarian carcinoma is the most important cause of gynaecological cancer-related mortality in Western societies. The age at diagnosis, extent of disease (as expressed by FIGO state), success of primary surgery and the histopathological features of the tumour are important prognostic markers. The majority of patients with ovarian cancer present with advanced disease (FIGO stage III/IV) and in this group of patients the median survival is only three years. New treatment approaches are therefore required to improve outcome in this disease. Angiogenesis, the development of a neovascular blood supply, is a critical step in the propagation of malignant tumour growth and metastasis and represents a promising target. This review will focus on angiogenesis, VEGF biology and the potential value of angiogenic factors with prognostic value in ovarian cancer.

Vascular endothelial growth factor (VEGF) enhances gastric carcinoma invasiveness via integrin alpha(v)beta6

Integrins play an important role in tumor metastasis induced by vascular endothelial growth factor (VEGF). However, in the case of gastric cancer, the precise role of VEGF in regulating integrin alphavbeta6 is unclear. In this study, we found that most of the alphavbeta6 integrin-positive gastric cancer tissues were also VEGF-positive. Furthermore, when gastric carcinoma cells were exposed to VEGF, expression of alphavbeta6 integrin was up-regulated and the extracellular signal-related kinase (ERK) pathway was activated. When integrin alphavbeta6 was blocked either with beta6 siRNA or anti-alphavbeta6 antibody, the migration of tumor cells normally induced by VEGF, as well as the activation of ERK, were markedly inhibited. Blocking the ERK signaling pathway significantly inhibited cell mobility. Taken together, the data suggest that VEGF is critical to the invasive process in human gastric cancer and that this occurs via up-regulation of integrin alphavbeta6 expression and activation of ERK.

Targeting aromatase and estrogen signaling in human non-small cell lung cancer

Lung cancer has become increasingly common in women, and gender differences in the physiology and pathogenesis of the disease have suggested a role for estrogens. In the lung recent data have shown local production of estrogens from androgens via the action of aromatase enzyme and higher levels of estrogen in tumor tissue as compared with surrounding normal lung tissue. High levels of aromatase expression are also maintained in metastases as compared with primary tumors. Consistent with these findings, clinical studies suggest that aromatase expression may be a useful predictive biomarker for prognosis in the management of non-small cell lung cancer (NSCLC), the most common form of lung malignancy. Low levels of aromatase associate with a higher probability of long-term survival in older women with early stage NSCLC. Treatment of lung NSCLC xenografts in vivo with an aromatase inhibitor (exemestane) alone or combined with standard cisplatin chemotherapy elicits a significant reduction in tumor progression as compared to paired controls. Further, lung cancer progression is also governed by complex interactions between estrogen and growth factor signaling pathways to stimulate the growth of NSCLC as well as tumor-associated angiogenesis. We find that combination therapy with the multitargeted growth factor receptor inhibitor vandetanib and the estrogen receptor antagonist fulvestrant inhibit tumor growth more effectively than either treatment administered alone. Thus, incorporation of antiestrogen treatment strategies in standard antitumor therapies for NSCLC may contribute to improved patient outcome, an approach that deserves to be tested in clinical trials.

Effects of human midkine on spontaneous resorption of herniated intervertebral discs

This study was performed in 36 rabbits to investigate the role of midkine (MK) in the resorption of herniated intervertebral discs. The L(1-2) disc was excised and immersed in one of three kinds of solution for two hours before relocation into the L4 epidural space. In the MK-treated group, the weight of relocated intervertebral discs decreased more over time than in the control group. Newly formed vessels and inflammatory cells were more frequently observed in the MK-treated group than in the control group two weeks after surgery. The degradation of matrix was more significant in the MK-treated group than in the control group four weeks after surgery. Larger areas were replaced by fibrous tissues in the MK-treated group eight weeks after surgery. Thus, MK can accelerate the resorption of the intervertebral disc relocation to the epidural space. Epidural injection of MK may contribute to the therapy of lumber disc herniation.

Expression of vascular endothelial growth factor in growth hormone-secreting pituitary adenomas: special reference to the octreotide treatment

OBJECTIVE

The present study was designed to investigate the localization of VEGF in GH-secreting pituitary adenomas and to evaluate the characteristic differences of VEGF expression in relation to the clinical effect of preoperative treatment with octreotide.

METHODS

Fifty-six cases of GH-secreting adenomas, which were divided into three groups and three normal pituitary glands, were studied using immunohistochemistry for expression of VEGF. The octreotide group consisted of 33 patients who received the octreotide before the surgery. The bromocriptine group consisted of 11 patients who received bromocriptine orally. The control groups consisted of 12 patients who were not treated with octreotide or bromocriptine pre-operatively. VEGF staining patterns for each specimen were examined under light microscopy and graded in a scale. These findings were correlated with clinical characteristics.

RESULTS

VEGF was displayed in a diffuse cytoplasmic pattern in all cases. VEGF staining was strongly seen in the cytoplasm in normal pituitary glands. Moderately positive staining with VEGF appeared in six of 33 (18%) cases of the octreotide group, and in eight of 12 (67%) cases of the control group. In contrast, weakly positive staining was observed in 25 of 33 (76%) cases of the octreotide group, and in three of 12 (25%) cases of the control group. The staining pattern differs statistically between the octreotide and control group, typically in densely granulated GH cell adenomas. Weak staining with VEGF appeared in all ten cases in which the tumor had shrunk. Age, gender, tumor size, tumor invasiveness and adenoma type did not influence VEGF expression.

CONCLUSION

We conclude that octreotide may inhibit the angiogenesis through down-regulation of VEGF.

Tumor-selective response to antibody-mediated targeting of alphavbeta3 integrin in ovarian cancer

The alpha(v)beta(3) integrin is expressed on proliferating endothelial cells and some cancer cells, but its expression on ovarian cancer cells and its potential as a therapeutic target are unknown. In this study, expression of the alpha(v)beta(3) integrin on ovarian cancer cell lines and murine endothelial cells was tested, and the effect of a fully humanized monoclonal antibody against alpha(v)beta(3), Abegrin (etaracizumab), on cell invasion, viability, tumor growth, and the Akt pathway were examined in vitro and in vivo. We found that etaracizumab recognizes alpha(v)beta(3) on the ovarian cancer cell lines SKOV3ip1, HeyA8, and A2780ip2 (at low levels) but not on murine endothelial cells. Etaracizumab treatment decreased ovarian cancer proliferation and invasion. In vivo, tumor-bearing mice treated with etaracizumab alone gave variable results. There was no effect on A2780ip2 growth, but a 36% to 49% tumor weight reduction in the SKOV3ip1 and HeyA8 models was found (P < .05). However, combined etaracizumab and paclitaxel was superior to paclitaxel in the SKOV3ip1 and A2780ip2 models (by 51-73%, P < .001) but not in the HeyA8 model. Treatment with etaracizumab was then noted to decrease p-Akt and p-mTOR in SKOV3ip1, but not in HeyA8, which is Akt-independent. Tumors resected after therapy showed that etaracizumab treatment reduced the proliferating cell nuclear antigen index but not microvessel density. This study identifies tumor cell alpha(v)beta(3) integrin as an attractive target and defines the Akt pathway as a predictor of response to function-blocking antibody.

Expression of VEGF and VEGFR2 in tumors during neoadjuvant therapy of patients with breast cancer

We revealed a significant positive correlation between the concentrations of tissue VEGF and its receptor VEGFR2 in the primary tumor. The degree and direction of changes in the content of VEGF and VEGFR2 in cytosols of tumors from patients with locally spread breast cancer during the preoperation therapy depended on initial levels of these parameters. We found that the expression of the studied factors depended on the degree of therapeutic pathomorphosis in the tumor tissue.

Bevacizumab and erlotinib: a promising new approach to the treatment of advanced NSCLC

Biologic agents that target molecules involved in tumor growth, progression, and pathological angiogenesis--such as the human epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF)--have demonstrated efficacy in patients with non-small cell lung cancer (NSCLC). Erlotinib (Tarceva); OSI Pharmaceuticals, Inc., Melville, NY, Genentech, Inc., South San Francisco, CA, and F. Hoffmann-La Roche Ltd, Basel, Switzerland), a highly selective tyrosine kinase inhibitor that inhibits EGFR, and bevacizumab (Avastin); Genentech, Inc., South San Francisco, CA, and F. Hoffmann-La Roche Ltd, Basel, Switzerland), a VEGF-targeted recombinant humanized monoclonal antibody, have displayed very encouraging activity in a randomized phase II trial in patients with previously treated NSCLC. Because erlotinib and bevacizumab act on two different pathways critical to tumor growth and dissemination, administering these drugs concomitantly may confer additional clinical benefits to cancer patients with advanced disease, by virtue of their complementary (or additive) antitumor activity. The combination of bevacizumab plus erlotinib may prove to be a viable second-line alternative to chemotherapy or erlotinib monotherapy in patients with NSCLC. The benefits of the combination may be further enhanced by selecting for patients who are likely to respond to this therapy. While a number of potential predictive markers have been identified for erlotinib, their value remains to be confirmed in prospective trials. In addition, the application of such personalized therapy will also depend on the availability of validated screening methods.

Vascular endothelial growth factor and breast cancer risk

Vascular endothelial growth factor (VEGF) is a key factor in angiogenesis and is important to carcinogenesis. Previous studies relating circulating levels of VEGF to breast cancer have been limited by small numbers of participants and lack of adjustment for confounders. We studied the association between serum VEGF and breast cancer in an unmatched case-control study of 407 pre- and postmenopausal women (n = 203 cases, n = 204 controls). Logistic regression was used to model the breast cancer risk as a function of natural log transformed VEGF levels adjusted for age, Gail score, education, physical activity, history of breastfeeding, serum testosterone, and hormone therapy (HT) use. The majority of the population was postmenopausal (67.6%) and the average age was 56 years; age and menopausal status were similar among cases and controls. Geometric mean VEGF levels were non-significantly higher in cases (321.4 pg/ml) than controls (291.4 pg/ml; p = 0.21). In a multivariable model, the odds of breast cancer was 37% higher for women with VEGF levels > or =314.2 pg/ml compared to those with levels below 314.2 pg/ml, albeit not significantly (p = 0.16). There was no interaction between VEGF and menopausal status (p = 0.52). In this case-control study, VEGF was not significantly associated with breast cancer risk in pre- and postmenopausal women.

Effects of a cyclooxygenase-1-selective inhibitor in a mouse model of ovarian cancer, administered alone or in combination with ibuprofen, a nonselective cyclooxygenase inhibitor

Nonsteroidal anti-inflammatory drugs (NSAIDs) are known to be potent inhibitors of the cyclooxygenases. The present study was designed to investigate the effects of a cyclooxygenase (COX)-1 inhibitor, SC-560, administered alone or in combination with ibuprofen on the growth inhibition of s.c. human ovarian SKOV-3 carcinoma and on angiogenesis. The effects of SC-560 and ibuprofen on tumor growth inhibition have been examined in mouse ovarian cancer models. Angiogenesis of both COX inhibitors was measured by reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. Prostaglandin E(2) (PGE(2)) levels in tumor tissues of mice were also determined by ELISA. The inhibitory rates in SC-560 group alone and in combination with ibuprofen group were 21.21% and 41.55%, respectively. In combination therapy with SC-560 and ibuprofen, tumor volumes were significantly reduced compared with that of control group (P < 0.05). In treatment groups, both COX inhibitors significantly reduced intratumor PGE(2) levels (all P < 0.01). Microvessel density (MVD) in tumor tissues were significantly decreased from 80.90 +/- 5.14 in vehicle-treated to 40.70 +/- 10.45 and 38.90 +/- 8.41 in SC-560 group alone and combination ibuprofen therapy (all P < 0.01). Ibuprofen was similar to the cyclooxygenase-1-selective inhibitor SC-560 in its ability to suppress the values of MVD of tumor tissues. SC-560 administered alone or in combination with ibuprofen inhibited the COX-associated up-regulation of VEGF. These studies demonstrate synergism between two COX inhibitors and that antiangiogenic therapy can be used to inhibit ovarian cancer growth.

A compartment model of VEGF distribution in blood, healthy and diseased tissues

BACKGROUND

Angiogenesis is a process by which new capillaries are formed from pre-existing blood vessels in physiological (e.g., exercise, wound healing) or pathological (e.g., ischemic limb as in peripheral arterial disease, cancer) contexts. This neovascular mechanism is mediated by the vascular endothelial growth factor (VEGF) family of cytokines. Although VEGF is often targeted in anti-angiogenic therapies, there is little knowledge about how its concentration may vary between tissues and the vascular system. A compartment model is constructed to study the VEGF distribution in the tissue (including matrix-bound, cell surface receptor-bound and free VEGF isoforms) and in the blood. We analyze the sensitivity of this distribution to the secretion rate, clearance rate and vascular permeability of VEGF.

RESULTS

We find that, in a physiological context, VEGF concentration varies approximately linearly with the VEGF secretion rate. VEGF concentration in blood but not in tissue is dependent on the vascular permeability of healthy tissue. Model simulations suggest that relative VEGF increases are similar in blood and tissue during exercise and return to baseline within several hours. In a pathological context (tumor), we find that blood VEGF concentration is relatively insensitive to increased vascular permeability in tumors, to the secretion rate of VEGF by tumors and to the clearance. However, it is sensitive to the vascular permeability in the healthy tissue. Finally, the VEGF distribution profile in healthy tissue reveals that about half of the VEGF is complexed with the receptor tyrosine kinase VEGFR2 and the co-receptor Neuropilin-1. In diseased tissues, this binding can be reduced to 15% while VEGF bound to the extracellular matrix and basement membranes increases.

CONCLUSION

The results are of importance for physiological conditions (e.g., exercise) and pathological conditions (e.g., peripheral arterial disease, coronary artery disease, cancer). This mathematical model can serve as a tool for understanding the VEGF distribution in physiological and pathological contexts as well as a foundation to investigate pro- or anti-angiogenic strategies.

Vascular endothelial growth factor expression in ovarian cancer: a model for targeted use of novel therapies?

PURPOSE

Angiogenesis has a vital role in tumor growth and metastasis, and vascular endothelial growth factor (VEGF) represents a potent cytokine in this process. However, the influence of VEGF in ovarian cancer remains controversial. Interest has focused on the use of antiangiogenic drugs in ovarian cancer. This study aims to establish the pattern of expression and effect on prognosis of VEGF in a large population of ovarian cancer patients and to potentially identify a cohort in whom antiangiogenic therapy is appropriate.

EXPERIMENTAL DESIGN

Using a tissue microarray of 339 primary ovarian cancers, the expression of VEGF was assessed immunohistochemically. Coupled to a comprehensive database of clinicopathologic variables, its effect on these factors and survival was studied.

RESULTS

Tumors expressing high levels of VEGF had significantly poorer survival (P = 0.04). Factors shown to predict prognosis independently of each other were age, International Federation of Gynecologists and Obstetricians stage, and the absence of macroscopic disease after surgery. VEGF was independently predictive of prognosis on multivariate analysis (P = 0.02). There was no correlation between VEGF and any clinicopathologic variable. High expression of VEGF was seen in only 7% of the tumors, suggesting that the role of antiangiogenic drugs may be limited to a small subset of patients.

CONCLUSION

High VEGF expression occurs in a small proportion of ovarian cancers, and this independently predicts poor prognosis. The small percentage of tumors with high levels of VEGF activity suggests that the role of bevacizumab may potentially be limited to a few patients; these patients could be targeted by molecular profiling.

Microenvironment changes (in pH) affect VEGF alternative splicing

Vascular endothelial growth factor-A (VEGF-A) has several isoforms, which differ in their capacity to bind extracellular matrix proteins and also in their affinity for VEGF receptors. Although the relative contribution of the VEGF isoforms has been studied in tumor angiogenesis, little is known about the mechanisms that regulate the alternative splicing process. Here, we tested microenvironment cues that might regulate VEGF alternative splicing. To test this, we used endometrial cancer cells that produce all VEGF isoforms as a model, and exposed them to varying pH levels, hormones, glucose and CoCl₂ (to mimic hypoxia). Low pH had the most consistent effects in inducing variations in VEGF splicing pattern (VEGF121 increased significantly, p < 0.001, when compared to VEGF145, 165 or 189). This was accompanied by activation of the p38 stress pathway and SR proteins (splicing factors) expression and phosphorylation. SF2/ASF, SRp20 and SRp40 down-regulation by siRNA impaired the effects of pH stimulation, blocking the shift in VEGF isoforms production. Taken together, we show for the first time that acidosis (low pH) regulates VEGF-A alternative splicing, may be through p38 activation and suggest the possible SR proteins involved in this process.

Serum vascular endothelial growth factor: a prognostic factor in cervical cancer

PURPOSE

To study pre-treatment serum VEGF of patients with invasive cervical cancer and its possible role as prognostic indicator.

METHODS

VEGF was measured using ELISA in the largest patient group (n = 167) to date.

RESULTS

Serum VEGF was significantly higher in advanced tumor stage (P = 0.01), large tumor size (tumors larger than 2 cm) (P = 0.03), and the presence of vascular space invasion (P = 0.05). Serum VEGF was associated with disease free and overall survival [DFS: Hazard Ratio (HR) = 2.61; 95% CI 1.32-5.17; P = 0.006; for OS: HR = 2.09; 95% CI 1.54-2.84; P < 0.001, respectively]. In multivariate Cox regression serum VEGF retained its prognostic value for DFS (HR = 2.10, P = 0.03) and OS (HR = 1.92, P = 0.04).

CONCLUSIONS

Serum VEGF levels correlate with more advanced and more aggressive disease in cervical cancer and may be a useful prognostic factor in patients with cervical cancer.

Molecular profiling of angiogenesis in hypericin mediated photodynamic therapy

BACKGROUND

Photodynamic therapy (PDT) involves the administration of a tumor-localizing photosensitizing drug, which is activated by light of specific wavelength in the presence of molecular oxygen thus generating reactive oxygen species that is toxic to the tumor cells. PDT selectively destroys photosensitized tissue leading to various cellular and molecular responses. The present study was designed to examine the angiogenic responses at short (0.5 h) and long (6 h) drug light interval (DLI) hypericin-PDT (HY-PDT) treatment at 24 h and 30 days post treatment in a human bladder carcinoma xenograft model. As short DLI targets tumor vasculature and longer DLI induces greater cellular damage, we hypothesized a differential effect of these treatments on the expression of angiogenic factors.

RESULTS

Immunohistochemistry (IHC) results showed minimal CD31 stained endothelium at 24 h post short DLI PDT indicating extensive vascular damage. Angiogenic proteins such as vascular endothelial growth factor (VEGF), tumor necrosis growth factor-alpha (TNF-alpha), interferon-alpha (IFN-alpha) and basic fibroblast growth factor (bFGF) were expressed to a greater extent in cellular targeting long DLI PDT compared to vascular mediated short DLI PDT. Gene expression profiling for angiogenesis pathway demonstrated downregulation of adhesion molecules - cadherin 5, collagen alpha 1 and 3 at 24 h post treatment. Hepatocyte growth factor (HGF) and Ephrin-A3 (EFNA3) were upregulated in all treatment groups suggesting a possible activation of c-Met and Ephrin-Eph signaling pathways.

CONCLUSION

In conclusion, long DLI HY-PDT induces upregulation of angiogenic proteins. Differential expression of genes involved in the angiogenesis pathway was observed in the various groups treated with HY-PDT.

A phase II clinical trial of sorafenib in androgen-independent prostate cancer

PURPOSE

To determine if sorafenib is associated with a 4-month probability of progression-free survival, which is consistent with 50%, as determined by clinical, radiographic, and prostate-specific antigen (PSA) criteria in patients with metastatic androgen-independent prostate cancer (AIPC).

EXPERIMENTAL DESIGN

Patients with progressive metastatic AIPC were enrolled in an open-label, single-arm phase II study. Sorafenib was given continuously at a dose of 400 mg orally twice daily in 28-day cycles. Clinical assessment and PSA measurement were done every cycle whereas radiographic measurements were carried out every two cycles.

RESULTS

Twenty-two patients were enrolled in the study to date, completing a planned first stage of the trial. Baseline patient characteristics included a median age of 63.9 years (range, 50-77 years), Gleason score of 9 (range, 4-9.5), and PSA concentration of 53.3 ng/mL (range, 2-1,905 ng/mL). Fifty-nine percent of patients had received one prior chemotherapy regimen. Of the 21 patients with progressive disease, 13 progressed only by PSA criteria in the absence of evidence of clinical and radiographic progression. Two patients were found to have dramatic reduction of bone metastatic lesions as shown by bone scan, although they met PSA progression criteria at the time when scans were obtained. Toxicities likely related to treatment included one grade 3 hypertension; one grade 3 hand-foot syndrome; and grade 1/2 toxicities: fatigue, anorexia, hypertension, skin rash, nausea, and diarrhea. Results from in vitro studies suggested that PSA is not a good marker of sorafenib activity. The geometric mean exposure (AUC(0-12)) and maximum concentration (C(max)) were 9.76 h mg/L and 1.28 mg/L, respectively. The time to maximum concentration (t(max)) and accumulation ratio (after second dose) ranged from 2 to 12 h and 0.68 to 6.43, respectively.

CONCLUSIONS

Sorafenib is relatively well tolerated in AIPC with two patients showing evidence of improved bony metastatic lesions. Interpretation of this study is complicated by discordant radiographic and PSA responses. PSA may not be an adequate biomarker for monitoring sorafenib activity. Based on these observations, further investigation using only clinical and radiographic end points as progression criteria is warranted. Accrual to the second stage of trial is ongoing.

Randomized, double-blind, placebo-controlled phase II trial of maintenance sunitinib versus placebo after chemotherapy for patients with advanced urothelial carcinoma: scientific rationale and study design

Systemic chemotherapy is the primary treatment modality for patients with advanced urothelial cancer. However, despite a high initial response rate, durable responses are rare. Angiogenesis has been shown to be important in the development and progression of urothelial cancer. Sunitinib, an oral, multi-targeted, small-molecule inhibitor of multiple tyrosine kinases, is known to inhibit angiogenesis and therefore might decrease progression of urothelial cancer. This phase II trial was designed to investigate the role of sunitinib as maintenance therapy in patients with advanced urothelial cancer. The specific hypothesis of this trial is that sunitinib will decrease progression rates in patients with advanced urothelial cancer who have obtained stable disease or better after standard chemotherapy.

Interaction between the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor (VEGF) pathways: a rational approach for multi-target anticancer therapy

Over the last decade, the concept of targeted biological therapy for the treatment of cancer has emerged. However, a better understanding of these targets and their role in tumor cells and in the surrounding stromal cells is required. Two interesting biological targets are the epidermal growth factor receptor (EGFR) and the vascular endothelia growth factor (VEGF) and its receptors. A number of agents that target these pathways have been described. Many of these are currently in clinical trials and a few have recently been approved by the regulatory authorities in USA and in the European Union. The molecular pathways involved in the proliferation of cancer cells and in tumor-related angiogenesis are very complex and the interference with only a single step of these pathways may often reveal an insufficient therapeutic approach. Moreover, cancer cells have an inherent ability to harness different growth factor signaling pathways for growth advantage and cell survival, a process that may even be facilitated by the use of selective targeted agents. Because of these escape mechanisms, monotherapy with selective targeted agents is unlikely to be a fully effective cancer treatment. For these reasons, targeting different pathways is an attractive and effective therapeutic strategy with a strong rationale for investigating this approach in the clinic. This review focuses on the preclinical rationale of combining targeted agents such as EGFR and VEGF inhibitors in the treatment of cancer and on the clinical trials that have emerged from these studies.

Phosphatidylinositol inhibits vascular endothelial growth factor-A--induced migration of human umbilical vein endothelial cells

Phosphatidylinositol (PI), a phospholipid in component of cell membranes, is widely distributed in animals, plants, and microorganisms. Here, we examined in vitro whether PI inhibits the angiogenesis induced by vascular endothelial growth factor-A (VEGF-A). PI concentration-relatedly and significantly (at 10 and 30 microg/ml) inhibited VEGF-A-induced tube formation in a co-culture of human umbilical vein endothelial cells (HUVECs) and fibroblasts. PI also inhibited the migration, but not proliferation, induced in HUVECs by VEGF-A. Furthermore, PI at 30 microg/ml inhibited the VEGF-A-induced phosphorylation of serine/threonine protein kinase family protein kinase B (Akt) and p38 mitogen activate kinase (p38MAPK), key molecules in cell migration, but not phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), a key molecule in cell proliferation. These findings indicate that PI inhibits VEGF-induced angiogenesis by inhibiting HUVECs migration and that inhibition of phosphorylated-Akt and -p38MAPK may be involved in the mechanism. Therefore, PI may be expected to prevent some diseases caused by angiogenesis.

Endocan expression and relationship with survival in human non-small cell lung cancer

PURPOSE

We evaluated the expression of endocan, a soluble lung- and kidney-selective endothelial cell-specific dermatan sulfate proteoglycan, in non-small cell lung tumors compared with normal lung and studied the significance of high levels of circulating endocan in patients with non-small cell lung cancer.

MATERIAL AND METHODS

Endocan and vascular endothelial growth factor mRNA expression were evaluated by semiquantitative PCR in tumoral and nontumoral lung tissue samples from a first series of 24 patients submitted to curative surgery. Relationships between survival, time to tumor progression, and serum levels of endocan were evaluated in a second series of 30 previously untreated patients addressed for staging.

RESULTS

In non-small cell lung cancers, endocan mRNA was overexpressed compared with control lung. Immunohistochemistry shows that endocan was expressed only by tumor endothelium in all cases, especially in the periphery of the tumors, with no differences between adenocarcinoma and squamous cell carcinoma. Endocan and vascular endothelial growth factor mRNA expression was positively correlated in lung tumors. Serum endocan levels, as well as tumor, node, and metastasis status, were correlated with both survival and time to tumor progression. However, endocan serum level was not an independent prognostic factor due to its correlation with the presence of metastasis.

CONCLUSION

Endocan is overexpressed in non-small cell lung tumors compared with healthy lung and probably represents a response of tumoral endothelium to proangiogenic growth factor stimulation. Circulating levels of endocan might reflect tumor angiogenic stimulation and present prognostic significance.

Hypoxia-inducible factor-1alpha (HIF-1alpha) gene polymorphisms, circulating insulin-like growth factor binding protein (IGFBP)-3 levels and prostate cancer

BACKGROUND

The Hypoxia-inducible factor-1 (HIF-1) plays an important role in regulating angiogenesis in response to hypoxia. Two non-synonymous polymorphisms (P582S C-->T and A588T G-->A) in the coding region of the subunit 1alpha (HIF-1alpha) gene have been associated with enhanced stability of the protein and androgen-independent prostate cancer (CaP). Insulin-like growth factor binding protein (IGFBP)-3 mRNA is more abundantly expressed in hypoxia-related inflammatory angiogenesis and recent in vivo data suggest that IGFBP-3 has direct, IGF-independent inhibitory effects on angiogenesis.

METHODS

We examined the association of these polymorphisms with CaP among 1,072 incident cases and 1,271 controls, and further explored their joint associations with various prediagnostic plasma vascular endothelial growth factor (VEGF), IGF-I, and IGFBP-3 levels.

RESULTS

Neither the P582S nor the A588T polymorphism was associated with risk of overall or metastatic/fatal CaP. However, we found that, among men with the homozygous CC wild-type (but not CT/TT) of the HIF-1alpha P582S, higher IGFBP-3 levels (>/= vs. <median) were associated with a 28% (95% CI, 0.55-0.95; P(interaction) = 0.01) lower risk of overall CaP and a 53% (0.25-0.88; P(interaction) = 0.11) lower risk of metastatic and fatal CaP. The A588T polymorphism was too rare to assess interactions.

CONCLUSIONS

The two HIF-1alpha gene polymorphisms were not directly associated with CaP, but the interaction between the P582S polymorphism and IGFBP-3 merits further evaluation in mechanistic studies.

Role of VEGF in small bowel adaptation after resection: the adaptive response is angiogenesis dependent

Previous work in our group has demonstrated that mouse salivary gland has the highest concentration of salivary-derived VEGF protein compared with other organs and is essential for normal palatal mucosal wound healing. We hypothesize that salivary VEGF plays an important role in maintaining the integrity of the gastrointestinal mucosa following small bowel resection (SBR). Thirty-five 8- to 10-wk-old C57BL/6 female mice were divided into seven treatment groups: 1) sham (transaction and anastomosis, n = 5); 2) SBR (n = 8); 3) sialoadenectomy and small bowel resection (SAL+SBR, n = 8); 4) sialoadenectomy and small bowel resection with EGF supplementation (SAL+SBR+EGF, n = 9); 5) sialoadenectomy and small bowel resection with VEGF supplementation (SAL+SBR+VEGF, n = 9); 6) sialoadenectomy and small bowel resection supplemented with EGF and VEGF (SAL+ SBR+VEGF+EGF, n = 6); 7) selective inhibition of VEGF in the submandibular gland by Ad-VEGF-Trap following small bowel resection (Ad-VEGF-Trap+SBR, n = 7). Adaptation was after 3 days by ileal villus height and crypt depth. The microvascular response was evaluated by CD31 immunostaining and for villus-vessel area ratio by FITC-labeled von Willebrand factor immunostaining. The adaptive response after SBR was significantly attenuated in the SAL group in terms of villus height (250.4 +/- 8.816 vs. 310 +/- 19.35, P = 0.01) and crypt depth (100.021 +/- 4.025 vs. 120.541 +/- 2.82, P = 0.01). This response was partially corrected by orogastric VEGF or EGF alone. The adaptive response was completely restored when both were administered together, suggesting that salivary VEGF and EGF both contribute to intestinal adaptation. VEGF increases the vascular density (6.4 +/- 0.29 vs. 6.1 +/- 0.29 vs. 5.96 +/- 0.20) and villus-vessel area ratio (0.713 +/- 0.01 vs. 0.73 +/- 0.01) in the adapting bowel. Supplementation of both EGF and VEGF fully rescues adaptation, suggesting that the adaptive response may be dependent on VEGF-driven angiogenesis. These results support a previously unrecognized role for VEGF in the small bowel adaptive response.

Angiogenesis Inhibitor Therapies: Focus on Kidney Toxicity and Hypertension

Angiogenesis inhibitors that target the epidermal growth factor (EGF) receptor (EGFR) and vascular endothelial growth factor (VEGF) constitute an important addition to the therapeutic armamentarium for the treatment of patients with metastatic disease. However, because the same growth factors are expressed in the kidneys, these treatment molecules have renal side effects. EGFR is expressed mainly in tubules (mainly distal and collecting segments) and mesangial and parietal epithelial cells. EGF is involved in maintaining tubular integrity and is a potent mitogen for cultured mesangial cells. Few cases of acute renal failure have been reported related to EGFR inhibitors. VEGF and VEGF receptors are still highly expressed in the kidney. VEGF is expressed in podocytes in the glomerulus, and VEGF receptors are present on endothelial, mesangial, and peritubular capillary cells. Signaling between endothelial cells and podocytes is essential for the proper development and maintenance of the filtration function of the kidney glomerulus. The most common renal class effects of VEGF antagonists are both manageable; hypertension and proteinuria commonly regressive on drug withdrawal. There was a dose-dependent increase in risk of proteinuria and hypertension in patients with cancer who received targeted therapies. Furthermore, few patients with glomerulonephritis or thrombotic microangiopathy secondary to treatment were reported. Hypertension is believed to be nitric oxide dependent, whereas proteinuria seems to be related to downregulation of podocyte tight junction protein. This article reviews data relating to hypertension and proteinuria associated with the use of these drugs.

New molecular targets and novel agents in the treatment of advanced urothelial cancer

Standard cytotoxic regimens for metastatic bladder cancer, such as gemcitabine/cisplatin or methotrexate, vinblastine, doxorubicin, and cipslatin (M-VAC), yield impressive overall response rates of 45% to 70%. Despite this, long-term, disease-free, overall survival is rare, and most patients eventually succumb to the disease. Much work has been undertaken evaluating the clinical and molecular factors associated with progressive bladder cancer, and this has, in turn, led to the development of both novel targets and agents. These include standard cytotoxics such as pemetrexed, an antifolate and antimetabolite agent that has demonstrated an overall response rate of 30% in early studies, and small-molecule tyrosine kinase inhibitors such as sunitinib, which will be studied as maintenance therapy for patients who respond to first-line chemotherapy. The evaluation of new targets and new agents in the midst of limited patient, logistical, and financial resources will be one of the more difficult challenges for investigators over the next several years.

Poorly versus moderately differentiated hepatocellular carcinoma: vascularity assessment by computed tomographic hepatic angiography in correlation with histologically counted number of unpaired arteries

PURPOSE

To determine the vascularity of moderately and poorly differentiated hepatocellular carcinoma (mHCC and pHCC, respectively) as observed on and depicted by computed tomography during hepatic angiography and to perform pathological correlation.

MATERIALS AND METHODS

Eighty-seven consecutive patients with 89 hepatocellular carcinomas (61 mHCCs and 28 pHCCs) were surgically resected in our hospital. The degree of contrast enhancement on computed tomography during hepatic angiography of the tumors was classified into high attenuation (H), isoattenuation (I), and low attenuation (L). We also examined hepatocellular carcinomas measuring less than 4 cm in diameter. Pathologically, the number of unpaired arteries in the tumors was determined (x200 magnification).

RESULTS

The number of mHCC and pHCC in each degree of enhancement (H/I/L) was 59:1:1 and 19:6:3, respectively. The number of mHCC and pHCC measuring less than 4 cm without portal invasion was 48 and 15, respectively; the number of these tumors in each degree of enhancement (H/I/L) was 47:1:0 and 11:3:1, respectively. The mean number of unpaired arteries was 8.9 +/- 4.4 in mHCC and 5.2 +/- 4.3 in pHCC, respectively. All results were statistically significant (P < 0.01).

CONCLUSIONS

Our results indicated that the arterial blood supply of pHCC was lower than that of mHCC.

Study of microcirculation in oral lichen planus by video-capillaroscopy

OBJECTIVE

The aim of this study was to evaluate "in vivo" the oral microcirculatory characteristics in patients with oral lichen planus (OLP) and to discover any differences in microcirculation in comparison with healthy patients.

STUDY DESIGN

Twenty patients with established diagnosis of OLP and 20 healthy patients were examined in our laboratory by means of contact optical probe videocapillaroscopy. The examined areas for each patient were the right and the left buccal mucosae. Capillary density and total capillary diameter, as well as afferent and efferent loop diameter were studied; the discovery of characteristic (tortuous, branched) loops was also investigated.

RESULTS

The results were observed by 2 different researchers using the capillaroscope's software. Capillary density and the diameter of the afferent and efferent ansa were found to be significantly increased in OLP patients compared with controls. There was also a significant difference between the study of capillary tortuousity and the discovery of characteristic branched loops, indicating angiogenesis.

CONCLUSIONS

Our methodology allowed an in vivo observation of the angiogenesis. Angiogenesis was interpreted as an increase in capillary density, total vascular caliber, and afferent and efferent loop caliber; the discovery of tortuous, branched loops, indicating the angiogenic phenomenon in vivo, was particularly significant. The capillaroscopy in correspondence with the lesion can be a very important method in the evaluation of the microcirculation of the patients suffering from OLP.

Integrin alpha9beta1 directly binds to vascular endothelial growth factor (VEGF)-A and contributes to VEGF-A-induced angiogenesis

Vascular endothelial growth factor A (VEGF-A) is a potent inducer of angiogenesis. We now show that VEGF-A-induced adhesion and migration of human endothelial cells are dependent on the integrin alpha9beta1 and that VEGF-A is a direct ligand for this integrin. Adhesion and migration of these cells on the 165 and 121 isoforms of VEGF-A depend on cooperative input from alpha9beta1 and the cognate receptor for VEGF-A, VEGF receptor 2 (VEGF-R2). Unlike alpha3beta1or alphavbeta3 integrins, alpha9beta1 was also found to bind the 121 isoform of VEGF-A. This interaction appears to be biologically significant, because alpha9beta1-blocking antibody dramatically and specifically inhibited angiogenesis induced by VEGF-A165 or -121. Together with our previous findings that alpha9beta1 directly binds to VEGF-C and -D and contributes to lymphangiogenesis, these results identify the integrin alpha9beta1 as a potential pharmacotherapeutic target for inhibition of pathogenic angiogenesis and lymphangiogenesis.

Antisense oligonucleotide targeting midkine suppresses in vivo angiogenesis

AIM: To evaluate the effect of antisense oligonucleotide targeting midkine (MK-AS) on angiogenesis in chick chorioallantoic membrane (CAM) and in situ human hepatocellular carcinoma (HCC).

METHODS: An in situ human hepatocellular carcinoma (HCC) model and CAM assay were used in this experiment. The effect of MK-AS on angiogenesis was evaluated by cell proliferation assay and hematoxylin-eosin (HE) staining.

RESULTS: MK-AS significantly inhibited human umbilical vein endothelial cells (HUVEC) and in situ human HCC growth. At the same time, MK-AS suppressed the angiogenesis both in human hepatocellular carcinoma cell line (HEPG2)-induced CAM and in situ human HCC tissues.

CONCLUSION: MK-AS is an effective antiangiogenesis agent in vivo.

Tumour angiogenesis: the relevance to surgeons

INTRODUCTION

Angiogenesis is the process of new blood vessel formation from pre-existing vessels, and is a key feature of malignant tumours. Surgeons involved in the management of patients with malignant disease need to be aware of angiogenic mechanisms and their surgical implications.

PATIENTS AND METHODS

A literature search was used to review recent developments in our understanding of the factors and processes involved in tumour angiogenesis, and how these will impact on the care of patients with malignant disease encountered by surgeons.

RESULTS

Angiogenesis is fundamental to all stages of the malignant process, and involves a complex interaction between mediators secreted by tumour cells and host cells. Intense investigation continues into therapies targeting components of the angiogenic cascade. Imaging modalities capable of measuring the angiogenic activity of a tumour are also being studied in order to predict prognosis and select suitable patients for anti-angiogenic therapy.

CONCLUSIONS

As the use of these anti-angiogenic therapies becomes more wide-spread, they may have implications on the healing rates of cutaneous wounds and intracorporeal anastomoses.

Ocular neovascularization: Implication of endogenous angiogenic inhibitors and potential therapy

Ocular neovascularization (NV) is the primary cause of blindness in a wide range of ocular diseases, such as diabetic retinopathy (DR) and age-related macular degeneration (AMD). The exact mechanism underlying the pathogenesis of ocular NV is not yet well understood, and as a consequence, there is no satisfactory therapy for ocular NV. In the last 10 years, a number of studies provided increasing evidence demonstrating that the imbalance between angiogenic stimulating factors and angiogenic inhibitors is a major contributor to the angiogenesis induced by various insults, such as hypoxia or ischemia, inflammation and tumor. The angiogenic inhibitors alone or in combination with other existing therapies are, therefore, believed to be promising in the treatment of ocular NV in the near future. This article reviews recent progress in studies on the mechanisms and treatment of ocular NV, focusing on the implication and therapeutic potential of endogenous angiogenic inhibitors in ocular NV.

Expression of vascular endothelial growth factor (VEGF) in locally invasive prostate cancer is prognostic for radiotherapy outcome

PURPOSE

Vascular endothelial growth factor (VEGF) is an important hypoxia-inducible pro-angiogenic protein that has been linked with an adverse survival outcome after radiotherapy in other cancer types: we hypothesized that this may also occur in prostate cancer. A retrospective study was, therefore, carried out to evaluate the potential of tumor VEGF expression to predict radiotherapy outcome in patients with high-risk prostate cancer.

METHODS AND MATERIALS

Fifty patients with locally advanced (T3 N0 M0) tumors of Gleason score > or =6, and who received radiotherapy alone as primary treatment for their disease, were studied. Vascular endothelial growth factor expression was assessed on pretreatment diagnostic tumor biopsies using a semiquantitative immunohistochemical scoring system. The results were analyzed in relation to clinicopathologic factors and patient outcome including biochemical failure and disease-specific mortality.

RESULTS

High VEGF expression was associated with a poor prognosis: in univariate log rank analysis, VEGF was the only significant prognostic factor for disease-specific survival (p = 0.035). High VEGF expression also associated with increased Gleason score (p = 0.02), but not posttreatment biochemical failure.

CONCLUSION

High tumor expression of VEGF identified patients at high risk of failure of treatment with radiotherapy. These patients might benefit from additional treatment approaches incorporating anti-angiogenic or hypoxia-specific agents.

Therapeutic Targets of Multiple Angiogenic Factors for the Treatment of Cancer and Metastasis

Like any growing healthy tissues, tumors build up their blood vessels by three mechanisms: angiogenesis, vasculogenesis, and intersucception. Vascular endothelial growth factor-A (VEGF-A) is one of the key factors responsible for stimulation and maintenance of the disorganized, leaky, and torturous tumor vasculature. In addition to VEGF-A, tumors produce multiple other factors to stimulate blood vessel growth. These include members in the platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), VEGF-C, insulin-like growth factor (IGF), angiopoietin (Ang), and hepatocyte growth factor (HGF) families. Recent studies show that these angiogenic factors can also promote lymphangiogenesis and potentially lymphatic metastasis. Understanding the roles of individual and combined angiogenic factors in promoting tumor angiogenesis is crucial for defining therapeutic targets and antiangiogenic drug development for the treatment of cancer.

Paclitaxel-carboplatin alone or with bevacizumab for non-small-cell lung cancer

BACKGROUND

Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, has been shown to benefit patients with a variety of cancers.

METHODS

Between July 2001 and April 2004, the Eastern Cooperative Oncology Group (ECOG) conducted a randomized study in which 878 patients with recurrent or advanced non-small-cell lung cancer (stage IIIB or IV) were assigned to chemotherapy with paclitaxel and carboplatin alone (444) or paclitaxel and carboplatin plus bevacizumab (434). Chemotherapy was administered every 3 weeks for six cycles, and bevacizumab was administered every 3 weeks until disease progression was evident or toxic effects were intolerable. Patients with squamous-cell tumors, brain metastases, clinically significant hemoptysis, or inadequate organ function or performance status (ECOG performance status, >1) were excluded. The primary end point was overall survival.

RESULTS

The median survival was 12.3 months in the group assigned to chemotherapy plus bevacizumab, as compared with 10.3 months in the chemotherapy-alone group (hazard ratio for death, 0.79; P=0.003). The median progression-free survival in the two groups was 6.2 and 4.5 months, respectively (hazard ratio for disease progression, 0.66; P<0.001), with corresponding response rates of 35% and 15% (P<0.001). Rates of clinically significant bleeding were 4.4% and 0.7%, respectively (P<0.001). There were 15 treatment-related deaths in the chemotherapy-plus-bevacizumab group, including 5 from pulmonary hemorrhage.

CONCLUSIONS

The addition of bevacizumab to paclitaxel plus carboplatin in the treatment of selected patients with non-small-cell lung cancer has a significant survival benefit with the risk of increased treatment-related deaths. (ClinicalTrials.gov number, NCT00021060.)

Overexpression of cyclooxygenase-2 correlates with tumor angiogenesis in endometrial carcinoma

The inducible enzyme cyclooxygenase-2 (COX-2) is an important mediator of angiogenesis and tumor growth. Several reports have indicated that vascular endothelial growth factor (VEGF)-positive tumors are associated with an increased amount of COX-2 protein. This study evaluated the significance of COX-2 in 34 patients with endometrial carcinoma and its relationship to angiogenesis. Immunohistochemical expression of COX-2 and VEGF was analyzed on paraffin-embedded tissue sections. Microvessel density (MVD) of endometrial carcinoma was also determined with anti-CD(34) as the label. COX-2 messenger RNA (mRNA) was analyzed by reverse transcription-polymerase chain reaction. The expression rate of COX-2 in 34 cases was 64.7% but not in control endometrium. COX-2 mRNA was higher in tumor specimens than in normal tissues. The level of COX-2 expression was higher in grade 2 tumors than in grade 3 tumors (P < 0.05). MVD was higher in COX-2-positive and VEGF-positive cases than in COX-2-negative and VEGF-negative cases (P < 0.05). The expression of COX-2 was positively correlated with the expression of VEGF and MVD (P < 0.05 and P < 0.01, respectively). The present findings suggest that overexpression of COX-2 may induce the expression of VEGF, increase angiogenesis, and enhance tumor growth.

Potential predictors of chemotherapy response in ovarian cancer--how do we define chemosensitivity?

OBJECTIVE

The aim of this study was to assess whether microvessel density (measured by CD31), vascular endothelial growth factor (VEGF) or multidrug resistance (MDR1) could determine the response to chemotherapy or act as prognostic factors in ovarian cancer.

METHODS

Seventy-nine ovarian specimens were immunostained. Pearson correlation, 1-way ANOVA and chi-square were used for univariate analysis. Kaplan Meier survival curves were used, log-rank was used for univariate analysis and a Cox proportional hazards regression model was used for multivariate evaluation. Response to chemotherapy was assessed after 6 months and again after 1 year.

RESULT

Quantifying VEGF proved to be a valuable independent prognostic indicator in progression-free survival (PFS) (p<0.05) and overall survival (OS) (p<0.0001). VEGF correlated with response to chemotherapy at the 6-month interval (r=0.446, p<0.001) but failed to correlate at the 1-year interval. Increased staining with CD31 was associated with decreased PFS (p<0.01) and OS (p<0.01) in univariate but not multivariate analysis. MDR1 failed to act as a prognostic marker or as a predictor of response to chemotherapy.

CONCLUSION

VEGF correlates with response to chemotherapy at the 6-month but not the 12-month interval. What should our criteria be for determining sensitivity to chemotherapy? CD31, VEGF and MDR1 do play a role in some ovarian malignancies but other factors are likely to be involved and perhaps molecular profiling will determine which factors will be important for determining the response to chemotherapy.

Combining targeted agents: blocking the epidermal growth factor and vascular endothelial growth factor pathways

Bevacizumab is a recombinant, humanized monoclonal antibody against vascular endothelial growth factor. Erlotinib HCl is a reversible, highly selective epidermal growth factor receptor tyrosine kinase inhibitor. Additionally, both agents have shown benefit in patients with previously treated non-small cell lung cancer (NSCLC). Preclinical data in xenograft models produced greater growth inhibition with the combination than with either agent alone. A phase I/II study in two centers examined combined erlotinib and bevacizumab treatment in patients with nonsquamous stage IIIB/IV NSCLC with one or more prior chemotherapy. In phase I, 150 mg/d erlotinib orally plus 15 mg/kg bevacizumab i.v. every 21 days was established as the phase II dose. A total of 40 patients were enrolled and treated in this study (34 patients at phase II dose): 21 were female, 30 had adenocarcinoma histology, 9 were never smokers, and 22 had two or more prior regimens. The most common adverse events were mild to moderate rash, diarrhea, and proteinuria. Preliminary data showed no pharmacokinetic interaction between erlotinib and bevacizumab. Eight patients (20.0%) had partial responses and 26 (65.0%) had stable disease as their best response. The median overall survival for the 34 patients treated at the phase II dose was 12.6 months, with progression-free survival of 6.2 months. Encouraging antitumor activity and safety of erlotinib plus bevacizumab support further development of this combination for patients with advanced NSCLC. A randomized phase II trial has been completed, and a phase III trial is ongoing.