Phase I Study of Antisense Oligonucleotide Against Vascular Endothelial Growth Factor: Decrease in Plasma Vascular Endothelial Growth Factor With Potential Clinical Efficacy

Macrophages and angiogenesis in human lymphomas

A link exists between chronic inflammation and cancer and immune cells, angiogenesis, and tumor progression. In hematologic malignancies, tumor-associated macrophages (TAMs) are a significant part of the tumor microenvironment. Macrophages are classified into M1/classically activated and M2/alternatively activated. In tumors, TAMs are mainly constituted by M2 subtype, which promotes angiogenesis, lymphangiogenesis, repair, and remodeling, suppressing adaptive immunity, increasing tumor cell proliferation, drug resistance, histological malignancy, and poor clinical prognosis. The aim of our review article is to define the role of TAMs and their relationship with the angiogenesis in patients with lymphoma reporting both an analysis of main published data and those emerging from our studies. Finally, we have discussed the anti-angiogenic approach in the treatment of lymphomas.

Suppressing VEGF-A/VEGFR-2 Signaling Contributes to the Anti-Angiogenic Effects of PPE8, a Novel Naphthoquinone-Based Compound

Natural naphthoquinones and their derivatives exhibit a broad spectrum of pharmacological activities and have thus attracted much attention in modern drug discovery. However, it remains unclear whether naphthoquinones are potential drug candidates for anti-angiogenic agents. The aim of this study was to evaluate the anti-angiogenic properties of a novel naphthoquinone derivative, PPE8, and explore its underlying mechanisms. Determined by various assays including BrdU, migration, invasion, and tube formation analyses, PPE8 treatment resulted in the reduction of VEGF-A-induced proliferation, migration, and invasion, as well as tube formation in human umbilical vein endothelial cells (HUVECs). We also used an aorta ring sprouting assay, Matrigel plug assay, and immunoblotting analysis to examine PPE8’s ex vivo and in vivo anti-angiogenic activities and its actions on VEGF-A signaling. It has been revealed that PPE8 inhibited VEGF-A-induced micro vessel sprouting and was capable of suppressing angiogenesis in in vivo models. In addition, PPE8 inhibited VEGF receptor (VEGFR)-2, Src, FAK, ERK1/2, or AKT phosphorylation in HUVECs exposed to VEGF-A, and it also showed significant decline in xenograft tumor growth in vivo. Taken together, these observations indicated that PPE8 may target VEGF-A–VEGFR-2 signaling to reduce angiogenesis. It also supports the role of PPE8 as a potential drug candidate for the development of therapeutic agents in the treatment of angiogenesis-related diseases including cancer.

Design, synthesis and biological evaluation of 4-phenoxy-pyridine/pyrimidine derivatives as dual VEGFR-2/c-Met inhibitors

A class of 4-phenoxy-pyridine/pyrimidine derivatives (23a–23p and 24a–24h) were designed, synthesized and evaluated as potent dual VEGFR-2/c-Met inhibitors.

The Emerging Landscapes of Long Noncoding RNA in Thyroid Carcinoma: Biological Functions and Clinical Significance

Thyroid carcinoma (TC) is one of the most prevalent primary endocrine tumors, and its incidence is steadily and gradually increasing worldwide. Accumulating evidence has revealed the critical functions of long noncoding RNAs (lncRNAs) in the tumorigenesis and development of TC. Many TC-associated lncRNAs have been documented to be implicated in TC malignant behaviors, including abnormal cell proliferation, enhanced stem cell properties and aggressiveness, and resistance to therapeutics, through interaction with proteins, DNA, or RNA or encoding small peptides. Therefore, further elucidating the lncRNA dysregulation sheds additional insights into TC tumorigenesis and progression and opens new avenues for the early diagnosis and clinical therapy of TC. In this review, we summarize the abnormal expression of lncRNA in TC and the fundamental characteristics in TC tumorigenesis and development. Additionally, we introduce the potential prognostic and therapeutic significance of lncRNAs in TC.

Anti-angiogenic Agents: A Review on Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) Inhibitors

Tumor growth inhibition can be achieved by inhibiting angiogenesis, which has been a field of great concern in recent years. Important targets to inhibit angiogenesis include vascular endothelial growth factor receptor (VEGFR) and its homologous tyrosine kinase receptor. Anti-angiogenic therapy based on inhibition of VEGFR-2 is an effective clinical treatment strategy. The research progress of VEGFR-2 inhibitors is reviewed in this paper from the aspects of drug development and chemical synthesis.

Chondrosarcoma-from Molecular Pathology to Novel Therapies

Chondrosarcoma (CHS) is the second most common primary malignant bone sarcoma. Overall survival and prognosis of this tumor are various and often extreme, depending on histological grade and tumor subtype. CHS treatment is difficult, and surgery remains still the gold standard due to the resistance of this tumor to other therapeutic options. Considering the role of differentiation of CHS subtypes and the need to develop new treatment strategies, in this review, we introduced a multidisciplinary characterization of CHS from its pathology to therapies. We described the morphology of each subtype with the role of immunohistochemical markers in diagnostics of CHS. We also summarized the most frequently mutated genes and genome regions with altered pathways involved in the pathology of this tumor. Subsequently, we discussed imaging methods and the role of currently used therapies, including surgery and the limitations of chemo and radiotherapy. Finally, in this review, we presented novel targeted therapies, including those at ongoing clinical trials, which can be a potential future target in designing new therapeutics for patients with CHS.

A novel 2-aminobenzimidazole-based compound Jzu 17 exhibits anti-angiogenesis effects by targeting VEGFR-2 signalling

BACKGROUND AND PURPOSE

Recent development in drug discovery have shown benzimidazole to be an important pharmacophore,. Benzimidazole derivatives exhibit broad-spectrum pharmacological properties including anti-microbial, anti-diabetic and anti-tumour activity. However, whether benzimidazole derivatives are effective in suppressing angiogenesis and its underlying mechanisms remain incompletely understood. In this study, we aim to characterize the anti-angiogenic mechanisms of a novel 2-aminobenzimidazole-based compound, Jzu 17, in an effort to develop novel angiogenesis inhibitor.

EXPERIMENTAL APPROACH

Effects of Jzu 17 on endothelial cell proliferation, migration, invasion, and activation of signalling molecules induced by VEGF-A, were analysed by immunoblotting, MTT, BrdU, migration, and invasion assays. We performed tube formation assay, aorta ring sprouting assay, matrigel plug assay, and a mouse model of metastasis to evaluate ex vivo and in vivo anti-angiogenic effects of Jzu 17.

KEY RESULTS

Jzu 17 inhibited VEGF-A-induced cell proliferation, migration, invasion, and endothelial tube formation of HUVECs. Jzu 17 suppressed VEGF-A-induced microvessel sprouting ex vivo and attenuated VEGF-A- or tumour cell-induced neovascularization in vivo. Jzu 17 also reduced B16F10 melanoma lung metastasis. In addition, Jzu 17 inhibited the phosphorylation of VEGFR-2 and its downstream signalling molecules in VEGF-A-stimulated HUVECs. Results from computer modelling further showed that Jzu 17 binds to VEGFR-2 with high affinity.

CONCLUSIONS AND IMPLICATIONS

Jzu 17 may inhibit endothelial remodelling and suppress angiogenesis through targeting VEGF-A-VEGFR-2 signalling. These results also suggest Jzu 17 as a potential lead compound and warrant the clinical development of similar agents in the treatment of cancer and angiogenesis-related diseases.

Results of a prospective phase 2 study of pazopanib in patients with surgically unresectable or metastatic chondrosarcoma

BACKGROUND

This single-arm, multicenter, phase 2 study evaluated the safety and antitumor activity of pazopanib in patients with unresectable or metastatic conventional chondrosarcoma.

METHODS

Eligible patients had conventional chondrosarcoma of any grade with measurable tumors that were unresectable or metastatic. Patients with mesenchymal, dedifferentiated, and extraskeletal myxoid chondrosarcoma subtypes and patients who received prior tyrosine kinase inhibitor therapy were excluded. Pazopanib at 800 mg once daily was administered for 28-day cycles. Tumor responses were evaluated by local radiology assessments every 2 cycles. The primary endpoint was the disease control rate (DCR) at week 16 (4 cycles).

RESULTS

Forty-seven patients were enrolled. The DCR at 16 weeks was 43% (95% confidence interval [CI], 28%-58%), which was superior to the null hypothesis rate of 30%, but the 2-sided P value (exact test) was .09 (1-sided P = .045). One patient had a partial response. The median overall survival was 17.6 months (95% CI, 11.3-35.0 months), and the median progression-free survival was 7.9 months (95% CI, 3.7-12.6 months). Grade 3 or higher adverse events were infrequent; hypertension (26%) and elevated alanine aminotransferase (9%) were most common.

CONCLUSIONS

This study provides evidence of positive drug activity for pazopanib in conventional chondrosarcoma.

Angiogenesis in cutaneous T-cell lymphoma - proteomic approaches

Neoangiogenesis plays an important role in cutaneous lymphoma pathogenesis. Cutaneous T-cell lymphoma (CTCL) is characterized by the presence of malignant T-cell clones in the skin. Vascular microenvironment of lymphomas accelerates neoangiogenesis through several factors released by tumoral cells: VEGF family, bFGF and PIGF. Tumor stroma (fibroblasts, inflammatory and immune cells) also plays a crucial role, by providing additional angiogenic factors. The angiogenic process through the VEGF-VEGFR axis can promote survival, proliferation and metastasis via autocrine mechanisms in cutaneous lymphomas. Microvascular density (MVD) measures the neo-vascularization of cutaneous lymphoma, generated by the response of tumor cells, proangiogenic stromal cells, and benign T/B lymphocytes within the tumor inflammatory infiltrate. Pro-angiogenic proteins have been found to indicate the evolution and prognosis in patients with CTCL. In conclusion, anti-angiogenic therapeutic protocols can target tumor vasculature or malignant tumor cells directly or through a large number of combinations with other drugs. The integration of proteomics into clinical practice based on high-throughput technologies leads to the development of personalized medicine, adapting the specific biomarkers to the application of cancer-type specific individual drug targets.

Clinical benefit of antiangiogenic therapy in advanced and metastatic chondrosarcoma

Chondrosarcoma is the most common bone sarcoma in adults. Conventional chondrosarcoma, the commonest histological subtype, is largely resistant to anthracycline-based chemotherapy. There have been anecdotal reports of durable clinical benefit with antiangiogenic agents in this disease. A retrospective search of patients treated at three sarcoma referral centers was performed to identify patients with advanced chondrosarcoma treated with antiangiogenic agents. The aim of this study was to evaluate the efficacy and safety of antiangiogenic agents in advanced chondrosarcoma. Ten patients were identified; seven with conventional, one each with clear cell, extraskeletal mesenchymal chondrosarcoma and extraskeletal myxoid chondrosarcoma. The median progression-free survival for patients with conventional and clear cell sarcoma was 22.6 months. Median overall survival has not been met. Antiangiogenic therapy was well tolerated in this series of patients. Our retrospective data suggest that antiangiogenic therapy can provide prolonged clinical benefit in advanced chondrosarcoma patients. Further prospective trials are required to precisely define the role of this class of agent in advanced chondrosarcoma.

Outcome during and after anticoagulant therapy in cancer patients with incidentally found pulmonary embolism

Current guidelines suggest treating cancer patients with incidental pulmonary embolism comparably to patients with symptomatic pulmonary embolism.

We used the Registro Informatizado de Enfermedad TromboEmbólica (RIETE) registry to compare the rate of major bleeding and symptomatic pulmonary embolism during the course of anticoagulation and after its discontinuation in cancer patients with incidental pulmonary embolism.

As of March 2016, 715 cancer patients with incidental pulmonary embolism had been enrolled in RIETE. During the course of anticoagulant therapy (mean 235 days), the rate of major bleeding was higher than the rate of symptomatic pulmonary embolism (10.1 (95% CI 7.48–13.4) versus 3.17 (95% CI 1.80–5.19) events per 100 patient–years, respectively), and the rate of fatal bleeding was higher than the rate of fatal pulmonary embolism (2.66 (95% CI 1.44–4.52) versus 0.66 (95% CI 0.17–1.81) deaths per 100 patient-years, respectively). After discontinuing anticoagulation (mean follow-up 117 days), the rate of major bleeding was lower than the rate of symptomatic pulmonary embolism (3.00 (95% CI 1.10–6.65) versus 8.37 (95% CI 4.76–13.7) events per 100 patient-years, respectively); however, there were no differences in the rate of fatal events at one death each.

The risk/benefit ratio of anticoagulant therapy in cancer patients with incidental pulmonary embolism is uncertain and must be evaluated in further studies.

RNA-targeted therapeutics in cancer clinical trials: Current status and future directions

Recent advances in RNA delivery and target selection provide unprecedented opportunities for cancer treatment, especially for cancers that are particularly hard to treat with existing drugs. Small interfering RNAs, microRNAs, and antisense oligonucleotides are the most widely used strategies for silencing gene expression. In this review, we summarize how these approaches were used to develop drugs targeting RNA in human cells. Then, we review the current state of clinical trials of these agents for different types of cancer and outcomes from published data. Finally, we discuss lessons learned from completed studies and future directions for this class of drugs.

DNA and RNA derivatives to optimize distribution and delivery

Synthetic, complementary DNA single strands and short interfering RNA double strands have been found to inhibit the expression of animal, plant, and viral genes in cells, animals, and patients, in a dose dependent and sequence specific manner. DNAs and RNAs, however, are readily digested in biological systems. Hence, chemists are obliged to design and synthesize nuclease-resistant analogs of normal DNA (Fig. 1).

Comprehensive analysis of published studies involving systemic treatment for chondrosarcoma of bone between 2000 and 2013

BACKGROUND

The majority of patients with chondrosarcoma of bone have an excellent overall survival after local therapy. However, in case of unresectable locally advanced or metastatic disease the outcome is poor and limited treatment options exist. Therefore we conducted a survey of clinical phase I or II trials and retrospective studies that described systemic therapy for chondrosarcoma patients.

MATERIALS AND METHODS

Using PubMed, clinicaltrials.gov, the Cochrane controlled trial register and American Society of Clinical Oncology (ASCO) abstracts a literature survey was conducted. From the identified items, data were collected by a systematic analysis. We limited our search to semi-recent studies published between 2000 and 2013 to include modern drugs, imaging techniques and disease evaluations.

RESULTS

A total of 31 studies were found which met the criteria: 9 phase I trials, 11 phase II and 8 retrospective studies. In these studies 855 chondrosarcoma patients were reported. The tested drugs were mostly non-cytotoxic, either alone or in combination with another non-cytotoxic agent or chemotherapy. Currently two phase I trials, one phase IB/II trial and three phase II trials are enrolling chondrosarcoma patients.

CONCLUSION

Because chondrosarcoma of bone is an orphan disease it is difficult to conduct clinical trials. The meagre outcome data for locally advanced or metastatic patients indicate that new treatment options are needed. For the phase I trials it is difficult to draw conclusions because of the low numbers of chondrosarcoma patients enrolled, and at different dose levels. Some phase II trials show promising results which support further research. Retrospective studies are encouraged as they could add to the limited data available. Efforts to increase the number of studies for this orphan disease are urgently needed.

Anti-angiogenic therapy, a new player in the field of sarcoma treatment

Sarcomas encompass a heterogeneous family of mesenchymal malignancies. In metastatic disease improvement in outcome has been limited and there is a clear need for the development of new therapies. One potential target is angiogenesis, already an accepted target for treatment of more prevalent cancers. Multiple (pre)clinical studies focused on the role of angiogenesis and anti-angiogenic treatment in sarcomas. However, getting significant results is complicated due to the relatively small number of patients and the broad range of sarcoma subtypes. Recently, pazopanib has been approved for the treatment of advanced soft tissue sarcoma patients, which is an important step forward and paves the way for the introduction of anti-angiogenic treatment in sarcomas. However, more studies are needed to understand the biological mechanisms by which patients respond to angiogenic inhibitors and to detect markers of response. This review covers the knowledge that has been gained on the role of angiogenesis and anti-angiogenic therapy in sarcomas.

Development and strategies of VEGFR-2/KDR inhibitors

VEGF is an important signaling protein involved in both vasculogenesis and angiogenesis. As an essential receptor protein tyrosine kinase propagating cellular signal transduction processes, VEGFR-2 is a central target for drug discovery against tumor-associated angiogenesis. Since the autophosphorylation of VEGFR-2 represents a key step in this signal pathway that contributes to angiogenesis, the discovery of small molecule inhibitors that block this reaction has attracted great interest for novel drugs research and development. Advances in the understanding of catalytic cleft and the conformational changes of DFG motif have resulted in the development of small molecule inhibitors known as type I and type II. High-resolution crystal structures of various inhibitors in complex with the receptor offer an insight into the relationship among binding modes, inhibition mechanisms, activity, selectivity and resistance. To control selectivity, improve activity and introduce intellectual property novelty, the strategies for the further development are discussed through structural and conformational analysis in this review.

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.

Review of therapeutic strategies for osteosarcoma, chondrosarcoma, and Ewing's sarcoma

The most prevalent forms of bone cancer are osteosarcoma, chondrosarcoma, and Ewing’s sarcoma. Although chemotherapy and radiotherapy have replaced traditional surgical treatments, survival rates have undergone only marginal improvements. Current knowledge of the molecular pathways involved in each type of cancer has led to better approaches in cancer treatment. A number of cell signaling molecules are involved in tumorigenesis, and specific targets have been identified based on these signal transducers. This review highlights some of the important cellular pathways and potential therapeutic targets, tumor site-specific irradiation techniques, and novel drug delivery systems used to administer these drugs.

Strong cross-talk between angiogenesis and EBV: do we need different treatment approaches in lymphoma cases with EBV and/or high angiogenic capacity

Angiogenesis is the new blood vessels formation and is the critical event for the growth of malignant diseases and plays a key role in the development, invasion, and metastasis of malignant tumors. Epstein-Barr virus (EBV) is an important carcinogen causing to the some neoplastic disorders and lytically infected cells may contribute to the growth of EBV-associated malignancies, and this phenomenon is related with enhancing angiogenesis. Due to the strong cross-talk between angiogenesis and viral carcinogenesis and increased information about the angiogenesis and viral carcinogenesis in lymphomas, we need new therapeutic approaches to cases with lymphoma. Due to the strong cross-talk between angiogenesis and viral lymphomagenesis, this association was reviewed in this study.

Glioblastoma multiforme

Patients with newly diagnosed glioblastoma multiforme should undergo a maximal tumor resection and then, whenever possible, should be entered into a clinical trial. The current standard of care consists of external beam irradiation, to a total of 60 Gy over 6 weeks, in combination with low-dose daily temozolomide, followed by at least six cycles of adjuvant temozolomide. If radiotherapy and a temozolomide-based adjuvant regimen fail, the most active treatment approach appears to be bevacizumab and irinotecan. Molecular therapy, with drugs targeting growth factor receptors and critical signal transduction pathway mediators, is also under active investigation.

Vascular endothelial growth factors and receptors: anti-angiogenic therapy in the treatment of cancer

Vascular endothelial growth factors (VEGFs) are critical regulators of vascular and lymphatic function during development, in health and in disease. There are five mammalian VEGF ligands and three VEGF receptor tyrosine kinases. In addition, several VEGF co-receptors that lack intrinsic catalytic activity, but that indirectly modulate the responsiveness to VEGF contribute to the final biological effect. This review describes the molecular features of VEGFs, VEGFRs and co-receptors with focus on their role in the treatment of cancer.

Prognostic impact of CD31-positive microvessel density in follicular lymphoma patients treated with immunochemotherapy

BACKGROUND

Tumour-infiltrating mast cells (MCs) can remodel tumour microenvironment and growth by suppressing immune responses and potentiating angiogenesis. Furthermore, accumulation of MCs in follicular lymphoma (FL) correlates with unfavourable prognosis after immunochemotherapy. Here we investigated whether tumour vascularity is associated with MC content and outcome in FL patients treated with immunochemotherapy.

PATIENTS AND METHODS

Microvessel density (MVD) and MC content were determined immunohistochemically from pretreatment samples of 95 FL patients using CD31, CD34 and mast cell tryptase antibodies. Gene expression data from a separate set of 24 FL patients were analysed for comparison. All patients were treated with the combination of rituximab (R) and cyclophoshamide-doxorubicin-vincristine-prednisone (CHOP) chemotherapy.

RESULTS

Increased CD31+ MVD correlated positively with the number of tumour infiltrating MCs and CD34+ vessels, and negatively with the outcome. Overall survival and progression-free survival were significantly better among patients with low CD31+ MVDs. In multivariate analyses, CD31+ MVD had prognostic value independently of Follicular Lymphoma Prognostic Index but not of MC content. Consistent with the immunohistochemical data, high CD31/PECAM1 mRNA levels were associated with adverse outcome. Conversely, a positive prognostic impact of VEGF mRNA expression on the outcome was found.

CONCLUSION

Vascularity is associated with MC content and outcome in R-CHOP-treated FL patients.

Internally calibrated quantification of VEGF in human plasma by fluorescence immunoassays in disposable elastomeric microfluidic devices

Herein we report on a proof of principle for the reproducible quantification of Vascular Endothelial Growth Factor (VEGF) in human plasma by fluorescence sandwich immunoassays using disposable polydimethylsiloxane (PDMS) microfluidic chips. The system requires 100 times less sample than typical clinical blood tests, while its current quantification limit is established at 4pM. The in-built calibration method of spiking the plasma with known concentrations of commercially available antigen avoids common sources of error and improves the reliability of the test results. The demonstrated technique is important for immunoassay applications in fundamental scientific research and "point-of-care" (POC) biomedical diagnostics. In particular, the system is immediately applicable to microfluidic quantification of VEGF in human plasma in cancer studies.

Angiogenesis and antiangiogenic therapy in non-Hodgkin's lymphoma

Angiogenesis, the growth of new blood vessels, requires dynamic expansion, assembly and stabilization of vascular endothelial cells in response to proangiogenic stimuli. Antiangiogenic strategies have become an important therapeutic modality for solid tumors. While many aspects of postnatal pathological angiogenesis have been extensively studied in the context of nonhematopoietic neoplasms, the precise role of these processes in lymphoma pathogenesis is under active investigation. Lymphoma growth and progression is potentiated by at least two distinct angiogenic mechanisms: autocrine stimulation of tumor cells via expression of vascular endothelial growth factor (VEGF) and VEGF receptors by lymphoma cells, as well as paracrine influences of proangiogenic tumor microenvironment on both local neovascular transformation and recruitment of circulating bone marrow-derived progenitors. Lymphoma-associated infiltrating host cells including hematopoietic monocytes, T cells and mesenchymal pericytes have increasingly been associated with the pathogenesis and prognosis of lymphoma, in part providing perivascular guidance and support to neoangiogenesis. Collectively, these distinct angiogenic mechanisms appear to be important therapeutic targets in selected non-Hodgkin's lymphoma (NHL) subtypes. Understanding these pathways has led to the introduction of antiangiogenic treatment strategies into the clinic where they are currently under assessment in several ongoing studies of NHL patients.

New approaches to the treatment of human herpesvirus 8-associated disease

Human herpesvirus 8 (HHV-8, also known as Kaposi sarcoma-associated herpesvirus or KSHV) is the etiologic agent of Kaposi sarcoma (KS) and primary effusion lymphoma (PEL), as well as many cases of Castleman disease. Despite significant advances in understanding the biology and natural history of these diseases, current treatment options have important limitations, and strategies to prevent their development in high-risk individuals are lacking. This article reviews the scope of HHV-8-associated disease, as well as the efficacy of current treatment options. Finally, novel approaches to treatment and prevention are described, including antiviral agents, targeted molecular therapy and a combination of these modalities.

The clinical approach towards chondrosarcoma

This review provides an overview of the histopathology, classification, diagnostic procedures, and therapy of skeletal chondrosarcoma. Chondrosarcomas that arise de novo are primary chondrosarcomas, whereas chondrosarcomas developing superimposed on pre-existing benign cartilage neoplasms such as enchondromas or osteochondromas are referred to as secondary chondrosarcomas. Conventional chondrosarcomas can be categorized according to their location in bone into central, peripheral, and juxtacortical chondrosarcomas. Histological grading is related to prognosis; however, it is also subject to interobserver variability. Rare subtypes of chondrosarcoma, including dedifferentiated, mesenchymal, and clear cell chondrosarcoma, are discussed as well. Magnetic resonance imaging is necessary to delineate the extent of the intraosseous and soft tissue involvement preoperatively. Computed tomography is especially recommended in the pelvis and other flat bones where it may be difficult to discern the pattern of bone destruction and the presence of matrix mineralization. Wide, en-bloc excision is the preferred surgical treatment in intermediate- and high-grade chondrosarcoma. In low-grade chondrosarcoma confined to the bone, extensive intralesional curettage followed by local adjuvant treatment and filling the cavity with bone graft has promising long-term clinical results and satisfactory local control. Chondrosarcomas are relatively radiotherapy resistant; therefore, doses >60 Gy are needed in attempts to achieve local control after incomplete resection. Irradiation with protons or other charged particles seems beneficial in this curative situation. Chemotherapy is only possibly effective in mesenchymal chondrosarcoma, and is of uncertain value in dedifferentiated chondrosarcoma. Potential new systemic treatment targets are being discussed.

Small-molecule inhibition of proteasome and silencing by vascular endothelial cell growth factor-specific siRNA induce additive antitumor activity in multiple myeloma

Angiogenesis plays an important role in the pathogenesis and progression in multiple myeloma (MM), and MM cells secrete vascular endothelial growth factor (VEGF), which further promotes proliferation of the tumor cells. Therefore, we evaluated the anti-myeloma effect of VEGF small interfering RNA (siRNA) silencing in MM cells and whether it can be augmented by the additional application of bortezomib directed against the 26S proteasome. After transfection with VEGF siRNA, we observed a reduction of VEGF expression in all studied cell lines: OPM-2, RPMI-8226, INA-6, Jurkat, Raji, and Karpas-299, as well as in cells of MM and lymphoma patients. VEGF siRNA significantly induced apoptosis and inhibited proliferation in OPM-2 cells (P<0.0001), RPMI-8226 (P<0.0001), and INA-6 (P<0.01) versus controls. Cotreatment with VEGF siRNA and bortezomib in MM cells resulted in an exaggerated inhibition of proliferation and induction of apoptosis compared with VEGF siRNA or bortezomib alone (P<0.001). In addition, the combination of VEGF siRNA and bortezomib significantly (P<0.01) reversed multidrug resistance gene 1-dependent resistance of MM cells. Our data suggest that small-molecule inhibition of proteasome and silencing by VEGF-specific siRNA may be associated with an additive antitumor activity and might be a suitable target for new, therapeutic strategies using RNA interference in MM.

Prognostic significance of EBV-LMP1 and VEGF-A expressions in non-Hodgkin's lymphomas

BACKGROUND AND AIM

EBV is an important virus in the pathogenesis of NHL. VEGF-A is the essential factor in tumor angiogenesis. There is evidence of cross talk between angiogenesis and viral carcinogenesis. The viral latent protein LMP1, may play a role by inducing expression of angiogenic factors In this study EBV-LMP1 and VEGF-A expressions have been studied in cases with NHL and prognostic significance of these has been evaluated.

PATIENTS AND METHODS

One hundred seventy-seven cases (60 had low grade lymphoma (LGL), 117 had aggressive lymphoma (AL)) with NHL have been included in this analysis. Immunohistochemistry has been used for the detection of EBV and VEGF-A.

RESULTS

EBV was found in 25 cases (14%); 5 of 60 cases with LGL while 20 of 117 cases with AL had EBV positivity; (OR: 2.3, 95% CI: 0.8-6.3, p=0.113). VEGF-A expression was found in 108 cases (61%); 30 of 60 cases with LGL and 78 of 117 cases with AL showed VEGF-A expression. There was an association between VEGF-A and aggressive histology (OR: 2.0, 95% CI: 1.1-3.8, p=0.031). EBV positivity was associated with VEGF-A expression in diffuse large B cell lymphoma (DLBCL) (0.045). Mean Survival rates were shorter in EBV (+) and/or VEGF-A (+) cases.

COMMENT

Highly significant association between VEGF-A and EBV expression and survival rate, suggests an association between angiogenesis and viral lymphomagenesis. Targeting both the angiogenesis and EBV may be important in the therapy of cases with NHL expressing EBV and/or VEGF-A.

Antiangiogenic therapy and surgical practice

Background

Antiangiogenic therapy has become a reality with the recent introduction of bevacizumab, a monoclonal antibody against vascular endothelial growth factor.

Methods

Relevant medical literature from PubMed, National Institute for Health and Clinical Excellence and National Institutes of Health websites to August 2007 was reviewed.

Results and conclusions

Although often described as the fourth modality of treatment after surgery, radiotherapy and chemotherapy, many antiangiogenic drugs have failed to live up to expectations. Nevertheless, research continues and there are reasons to believe that antiangiogenic therapy may yet have a future in the clinical setting.

Update on chondrosarcomas

PURPOSE OF REVIEW

This paper reviews recent molecular, biologic, developmental therapeutic, and clinical findings in conventional and variant chondrosarcomas.

RECENT FINDINGS

The prognosis of chondrosarcomas traditionally correlates with histologic grade and adequacy of surgery. Newer markers of cell differentiation, activation, genetics, and cell signaling may offer important prognostic information. Translational research has validated platelet-derived growth factor receptor, estrogen signaling, matrix metalloproteinase-1, histone deacetylase, methylthioadenosine phosphorylase, and vascular endothelial growth factor-A as potential therapeutic targets. Bisphosphonates may also possess important antitumoral effects. Molecular studies have established that extraskeletal myxoid chondrosarcoma is a unique entity defined by the presence of a fusion gene between the orphan nuclear receptor, CHN/NOR1, and a promiscuous partner, most commonly EWSR1. Clinical studies have shown that development of second malignancies is an uncommon but real risk for chondrosarcoma survivors; the benefit of chemotherapy for dedifferentiated chondrosarcomas remains questionable; and late recurrences of clear cell chondrosarcomas emphasize the need for long-term follow up.

SUMMARY

Chondrosarcomas are a heterogeneous group of bone and soft tissue tumors. Recent advances in molecular diagnostics, pathobiology, and developmental therapeutics will aid both scientists and clinicians in improving the classification and therapy of this diverse family of cartilaginous tumors.

A review of the latest clinical compounds to inhibit VEGF in pathological angiogenesis

Angiogenesis plays an important role in the formation of new blood vessels and is crucial for tumour development and progression. Imbalance between pro- and antiangiogenesis factors regulates the biological process of angiogenesis. The best characterised of the proangiogenic factors and the most potent is vascular endothelial growth factor (VEGF). The binding of VEGF to one of its transmembrane tyrosine kinase receptors, which are predominantly found on endothelial cells, results in receptor dimerisation, activation and autophosphorylation of the tyrosine kinase domain. This triggers a cascade of complex downstream signalling pathways. Several strategies targeting the VEGF signalling pathway have been developed. These include neutralising antibodies to VEGF (bevacizumab) or VEGF receptors (VEGFRs) (DC101), soluble VEGFR/VEGFR hybrids (VEGF-Trap), and tyrosine kinase inhibitors of VEGFRs (BAY43-9006, SU11248, ZD6474, AZD2171, PTK/ZK and others). Several of these agents are now being investigated in clinical trials.

Predicting benefit from anti-angiogenic agents in malignancy

A high probability of benefit is desirable to justify the choice of anti-angiogenic therapy from an ever-expanding list of expensive new anticancer agents. However, biomarkers of response to cytotoxic agents are not optimal for predicting benefit from anti-angiogenic drugs. This discussion will focus on both preclinical and clinical research to identify biomarkers for anti-angiogenic therapies that can inform dosing, early clinical benefit, initial drug choice, emerging resistance and second-line treatments.