Current perspectives between metabolic syndrome and cancer.

Metabolic syndrome is a cluster of risk factors that lead to cardiovascular morbidity and mortality. Recent studies linked metabolic syndrome and several types of cancer. Although metabolic syndrome may not necessarily cause cancer, it is linked to poorer cancer outcomes including increased risk of recurrence and overall mortality. This review tends to discuss the major biological and physiological alterations involved in the increase of incidence and mortality of cancer patients affected by metabolic syndrome. We focus on metabolic syndrome-associated visceral adiposity, hyperinsulinemia, hyperglycemia, insulin-like growth factor (IGF-I) pathway as well as estrogen signaling and inflammation. Several of these factors are also involved in carcinogenesis and cancer progression. A better understanding of the link between metabolic syndrome and cancer may provide new insight about oncogenesis. Moreover, prevention of metabolic syndrome - related alterations may be an important aspect in the management of cancer patients during simultaneous palliative care.

HIF2α is involved in the expansion of CXCR4-positive cancer stem-like cells in renal cell carcinoma.

BACKGROUND: Hypoxia and the subsequent activation of hypoxia-inducible factor-2α (HIF2α) contribute to the progression of a variety of cancers. However, their role in the generation of renal cell carcinoma-derived stem cells has not been fully addressed. METHODS: A sphere formation assay, cell proliferation, RT-PCR, western blot, FACS, immunohistochemistry and tumour xenograft were used to study the role of HIF2α. RESULTS: Propagation of four renal cell carcinoma (RCC) cell lines (Caki-1, Caki-2, 786-O, 769-P) in anchorage-independent floating spheres led to the expansion of cells bearing the CXCR4 (CD184) surface marker. Inhibition of the CXCR4 pathway reduced sphere expansion. The enhanced self-renewal activity of the CXCR4-positive spheres was preceded by the upregulation of HIF2α. Knockdown of HIF2α abrogated CXCR4 expression and sphere formation. Finally, RCC-derived spheres showed an undifferentiated phenotype in vivo and formed subcutaneous tumours that highly expressed HIF2α and CXCR4. Inhibition of HIF2α abolished tumour growth in animal models. CONCLUSIONS: These results suggest that the generation of RCC-derived CSCs involves the activation of HIF2α and may provide a foundation for the development of new strategies to prevent the induction of CSCs in RCC.

Hyperglycemia promotes K-Ras-induced lung tumorigenesis through BASCs amplification.

Oncogenic K-Ras represents the most common molecular change in human lung adenocarcinomas, the major histologic subtype of non-small cell lung cancer (NSCLC). The presence of K-Ras mutation is associated with a poor prognosis, but no effective treatment strategies are available for K-Ras -mutant NSCLC. Epidemiological studies report higher lung cancer mortality rates in patients with type 2 diabetes. Here, we use a mouse model of K-Ras-mediated lung cancer on a background of chronic hyperglycemia to determine whether elevated circulating glycemic levels could influence oncogenic K-Ras-mediated tumor development. Inducible oncogenic K-Ras mouse model was treated with subtoxic doses of streptozotocin (STZ) to induce chronic hyperglycemia. We observed increased tumor mass and higher grade of malignancy in STZ treated diabetic mice analyzed at 4, 12 and 24 weeks, suggesting that oncogenic K-Ras increased lung tumorigenesis in hyperglycemic condition. This promoting effect is achieved by expansion of tumor-initiating lung bronchio-alveolar stem cells (BASCs) in bronchio-alveolar duct junction, indicating a role of hyperglycemia in the activity of K-Ras-transformed putative lung stem cells. Notably, after oncogene K-Ras activation, BASCs show upregulation of the glucose transporter (Glut1/Slc2a1), considered as an important player of the active control of tumor cell metabolism by oncogenic K-Ras. Our novel findings suggest that anti-hyperglycemic drugs, such as metformin, may act as therapeutic agent to restrict lung neoplasia promotion and progression.

Phase II escalation study of sorafenib in patients with metastatic renal cell carcinoma who have been previously treated with anti-angiogenic treatment.

OBJECTIVE: To assess both clinical and biological efficacy and toxicity of sorafenib in patients with metastatic renal cell carcinoma (mRCC) previously treated with an anti-angiogenic vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor. METHODS: Sorafenib is an orally active multikinase inhibitor approved for the treatment of mRCC. Drug-focused translational research on tissues (i.e. B-RAF) and plasma (VEGFR-α, circulating endothelial cells, endothelial progenitor cells) was performed to define biological predictive and prognostic markers and their related kinetics. Patients with mRCC pretreated with an anti-angiogenic treatment, an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0-2 and adequate organ function were eligible. Patients received sorafenib 400 mg twice a day continuously in 4-week cycles. Patients with no progressive disease at 12 weeks continued to receive sorafenib at the standard dose, whereas progressing patients received an increased dose (600 mg twice a day) with early disease restaging after 4 weeks. Patients who progressed at 600 mg twice a day went off study. Efficacy (overall tumour control) was assessed by Response Evaluation Criteria in Solid Tumors. RESULTS: In all, 19 patients were entered. The baseline characteristics were as follows: ECOG PS 0-1 94.8%; median (range) age 62 (41-81) years; nephrectomy 100%; surgery for metastatic disease 26.4%; clear cell 79.1%; papillary cell 15.7%; sarcomatoid/high grade 5.2%; two or more metastatic sites 84%. Overall, 11 patients (58%) had disease control at 6 months without significant correlation between response to prior therapy and hypertension. Progression-free survival (PFS) of 8.3 months was observed. Of six patients for whom the dose was escalated due to early progression, three benefitted with PFS of >3 months. Three (15.7%) of 19 patients had a V600E mutation and one had a K601E mutation; PFS appeared to be substantially shorter in these patients compared with 15 patients with wild-type B-RAF (2.5 vs 9.1 month, P < 0.05). The most common toxicity (National Cancer Institute Common Toxicity Criteria, NCIC 3.0, all patients) was grade ≥1 diarrhoea and grade 2-3 hand-foot syndrome in 11 patients. Grade 3 mucositis was observed in one patient. CONCLUSIONS: Sorafenib at doses of 400-600 mg twice a day continuously results in acceptable and well tolerated salvage treatment after VEGFR tyrosine kinase inhibitor failure. In progressive patients, treatment with a higher dose could be a valid option and B-RAF mutations may be an interesting predictive marker to be studied in a larger randomized trial.

The neuroimmune semaphorin-3A reduces inflammation and progression of experimental autoimmune arthritis.

Semaphorin-3A (Sema3A), a member of a large family of conserved proteins originally implicated in axon guidance, is expressed by activated T cells and downmodulates T cell activation in vitro. This study examined the effect and mechanism of action of Sema3A overexpression in a mouse model of collagen-induced arthritis. Prophylactic i.p. administration of plasmid DNA encoding Sema3A markedly reduced the incidence, disease severity, and articular inflammation compared with control plasmid without insert. Treatment of Sema3A reduced anticollagen IgG levels and suppressed collagen-specific proinflammatory cytokine (IFN-γ and IL-17) release, but increased IL-10 concentration in the serum. In line with results in arthritic mice, Sema3A expression is defective in CD4(+) T cells derived from patients with rheumatoid arthritis. In contrast, increased expression of the Sema3A receptor neuropilin-1 (NP-1) is detected in the same cells. The CD4(+)NP-1(+) T cells are a T cell subset involved in the control of the immune responses. They express greater amounts of IL-10 and show suppressive activities on autologous CD4(+) T cells. Sema3A acted directly on CD4(+)NP-1(+) T cells, because it could increase IL-10 production and influence the regulatory function on CD4(+) T cell growth. Therefore, I propose that Sema3A increases the CD4(+)NP-1(+) T cell ability to suppress alloresponses, that its transient expression is altered in rheumatoid inflammation, and that reintroduction of Sema3A is sufficient to attenuate collagen-induced arthritis, supporting its therapeutic potential in the treatment of autoimmune disorders.

Metronomic administration of zoledronic acid and taxotere combination in castration resistant prostate cancer patients: phase I ZANTE trial.

BACKGROUND: Docetaxel (DTX) and zoledronic acid (ZOL) are effective in patients with hormone resistant prostate cancer (HRPC) with bone metastases. A phase I clinical trial of metronomic administration of Zoledronic Acid AN d TaxoterE combination (ZANTE trial) in 2 different sequences was conducted in HRPC. RESULTS: The maximum tolerated dose was not achieved with sequence A. Two patients at third level of sequence B developed dose limiting toxicity. A disease control was obtained in six out of nine patients treated with sequence A, where a decrease of biological markers and PSA were also observed. No evidence of anti-tumor activity was observed in patients treated with sequence B. PATIENTS AND METHODS: Twenty-two patients enrolled into the study (median age: 73 years; range: 43-80) received one of three escalated doses of DTX (30, 40 and 50 mg/m(2)) in combination with a fixed dose of ZOL (2 mg), both administered every 14 days in two different sequences: DTX at the day 1 followed by ZOL at the day 2 (sequence A) or the reverse (sequence B). Patients were evaluated for adverse events and serum IL-8, MMP-2 and MMP-9 were evaluated prior and after therapy with the two sequences of administration of DTX and ZOL. CONCLUSIONS: The bi-weekly combination of DTX (50 mg/m(2)) followed by ZOL was feasible and show promising anti-tumor activity.

Lipoxygenase inhibitors for cancer prevention: promises and risks.

It is well established that an increase of n-6 polyunsaturated (i.e. arachidonic and arachidonic-converted linoleic acids) fat dietary intake enhances carcinogenesis and promotes tumorigenesis through oxidative metabolism. The Cyclooxygenase (COX) and Lipoxygenase (LOX) enzymes mediate the oxidative metabolism of n-6 polyunsaturated fatty acids and generate a cascade of biological active molecules. Nonsteroidal antiinflammatory drugs (NSAIDs) modulating arachidonic acid (AA) metabolism have been utilized in cancer chemoprevention. The gastrolesivity of a prolonged use of nonselective NSAIDs, due to the COX inhibition, an important housekeeping gene of the gastrointestinal system, contraindicated their use in chemoprevention. Moreover, cardiovascular side effects emerged in the long-term use of COX-2 specific inhibitors rising doubts on their use for cancer chemoprevention. This evidence renewed the interest into other AA-metabolizing pathways relevant in inflammation and carcinogenesis. Here, the role of the LOXs pathways in carcinogenesis is reviewed. Inhibition of the LOX pathways, alone or in association with COX-2 pathway, appears to be a promising field for detecting new molecular target and engineering new chemopreventive strategies on cancer.

The plexin-A1 receptor activates vascular endothelial growth factor-receptor 2 and nuclear factor-kappaB to mediate survival and anchorage-independent growth of malignant mesothelioma cells.

The semaphorins and their receptors, the neuropilins and the plexins, are constituents of a complex regulatory system that controls axonal guidance. Moreover, many types of tumor cells express various members of semaphorins and receptors, but the biological activities within tumor mass and the signal transduction mechanism(s) they use are largely unknown. Here, we show that in asbestos-related malignant pleural mesothelioma (MPM), Semaphorin-6D (Sema6D) and its receptor plexin-A1 are frequently expressed and trigger a prosurvival program that promotes anchorage-independent growth of MPM cells. Interestingly, the same response is also controlled by the tyrosine kinase receptors of vascular endothelial growth factor (VEGF) through a nuclear factor-kappaB (NF-kappaB)-dependent pathway. We found that in MPM cells, plexin-A1 and VEGF-receptor 2 (VEGF-R2) are associated in a complex. Moreover, the presence of Sema6D promotes the tyrosine phosphorylation of VEGF-R2 in a plexin-A1-dependent manner. This is necessary for basal and Sema6D-induced NF-kappaB transcriptional activity, and NF-kappaB mediates tumor cell survival. Expression of Sema6D and plexin-A1 is induced by asbestos fibers and overexpression of plexin-A1 in nonmalignant mesothelial cells inhibits cell death after asbestos exposure. This work identifies a new biological function of semaphorins in cancer cells and suggests the involvement of an undescribed survival pathway during MPM tumorigenesis.

Enhanced antitumor therapy by inhibition of p21waf1 in human malignant mesothelioma.

PURPOSE: The p21 cyclin-dependent kinase inhibitor was frequently expressed in human malignant pleural mesothelioma (MPM) tissues as well as cell lines. Recent data indicate that p21 keeps tumor cells alive after DNA damage, favoring a survival advantage. In this study, we assessed the possibility of p21 suppression as a therapeutic target for MPM. EXPERIMENTAL DESIGN: We established two different MPM-derived (from H28 and H2052 cells) subclones using vector-based short hairpin RNA (shRNA). Then, chemosensitivity against low doses of antineoplastic DNA-damaging agents was investigated by colony formation assays, and furthermore, the type of cell response induced by these drugs was analyzed. To examine the effect of p21 shRNA on chemosensitivity in vivo, tumor formation assays in nude mice were done. RESULTS: In colony formation assay, the IC50 of doxorubicin was 33 +/- 3.0 nmol/L in p21 shRNA-transfected cells with respect to 125 +/- 10 nmol/L of control vector-transfected cells. This enhancement of growth inhibition was achieved by converting a senescence-like growth arrest to apoptosis in response to doxorubicin, etoposide, and CPT11. In the in vivo assays, CPT11 and loss-of-expression of p21 in combination led to considerable suppression of tumor growth associated with a substantially enhanced apoptotic response, whereas CPT11 alone was ineffective at inducing these responses. CONCLUSIONS: These results indicated that p21 might play an important role in chemosensitivity to anticancer agents, and the suppression of its expression might be a potential therapeutic target for MPM.

Semaphorin3A signaling controls Fas (CD95)-mediated apoptosis by promoting Fas translocation into lipid rafts.

Semaphorins and their receptors (plexins) have pleiotropic biologic functions, including regulation of immune responses. However, the role of these molecules inside the immune system and the signal transduction mechanism(s) they use are largely unknown. Here, we show that Semaphorin3A (Sema3A) triggers a proapoptotic program that sensitizes leukemic T cells to Fas (CD95)-mediated apoptosis. We found that Sema3A stimulation provoked Fas translocation into lipid raft microdomains before binding with agonistic antibody or FasL (CD95L). Disruption of lipid rafts reduced sensitivity to Fas-mediated apoptosis in the presence of Sema3A. Furthermore, we show that plexin-A1, together with Sema3A-binding neuropilin-1, was rapidly incorporated into membrane rafts after ligand stimulation, resulting in the transport of actin-linking proteins into Fas-enriched rafts. Cells expressing a dominant-negative mutant of plexin-A1 did not show Fas clustering and apoptosis on Sema3A/Fas costimulation. This work identifies a novel biologic function of semaphorins and presents an unexpected signaling mechanism linking semaphorin to the tumor necrosis factor family receptors.

Integrin-mediated cell adhesion and spreading engage different sources of reactive oxygen species.

The tightly regulated production of intracellular reactive oxygen species (ROS) participates in several biologic processes such as cellular growth, programmed cell death, senescence, and adhesion. It is increasingly evident that the same enzymatic processes that were originally linked to ROS generation during host defence or apoptosis execution are also involved in redox-mediated signal transduction. We investigated in murine NIH3T3 fibroblasts the contribution of a variety of redox-dependent events during signal transduction initiated by integrin engagement due to fibronectin stimulation and report that a mitochondrial ROS release occurs, strictly confined to the early phase of extracellular matrix (ECM) contact (10 min). Besides, 5-lipoxygenase (5-LOX) is engaged by integrin receptor ligation as another ROS source, contributing to the more-intense, second ROS burst (45 min), possibly orchestrating the spreading of cells in response to ECM contact. To define a potential mechanism for ROS signaling, we demonstrate that on integrin recruitment, the Src homology-2 domain-containing phosphatase 2 (SHP-2) undergoes a reversible oxidization/inactivation to which mitochondrial and 5-lipoxygenase ROS contribute differentially. In keeping with a key role of oxidants during integrin signaling, the inactivation of SHP-2 prevents the dephosphorylation and inactivation of SHP-2 substrates (p125FAK and SHPS-1), thus enabling the continued propagation of the signal arising by integrin engagement.

Neuronal semaphorins regulate a primary immune response.

Semaphorins are involved in a wide range of biological processes, including axon guidance, neuronal migration, angiogenesis, cardio- and osteo-genesis. Recently they have also been found to be important for immune response. Sema3A reduces the activation of T cells through its cell-surface receptors, including members of the neuropilin and plexin families. By contrast, Sema4D (CD100), which is expressed on the surface of T, B and dendritic cells, increases B cell and dendritic cell function using either plexin B1 or CD72 as receptors. The transmembrane protein Sema4A is involved in the activation of immune cells through interactions with Tim-2. Emerging evidence also indicates that additional semaphorins and related molecules seem to function in the reciprocal stimulation of T cells and antigen-presenting cells (APCs). This paper discusses the functions of these semaphorins in the immune system, focusing on their roles in T cell-APC interactions.

Characterization of human malignant mesothelioma cell lines orthotopically implanted in the pleural cavity of immunodeficient mice for their ability to grow and form metastasis.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a tumor known to be resistant to conventional therapies. Thus, an in vivo model can represent an important tool for assessing the efficacy of novel approaches in the treatment of MPM.Presently, human MPM cells have been grown orthotopically in mice upon transplantation of tumor masses or tumor cell suspensions following surgery. In these models however, surgery can interfere with the tumor growth and the early stages of tumor development cannot be easily explored. Finally, results may not be so accurate due to implantation of potentially different tumor samples in different experimental groups.Our work aimed at establishing a nude mouse model xenotransplanted with human MPM cell lines in which tumor progression exhibits some features of the human disease. METHODS: Three distinct human MPM cell lines previously established from MPM patients displaying two different phenotypes, biphasic (MM-B1 and IST-Mes3) and epithelioid (IST-Mes2), were directly injected into the pleural cavity of nude mice. At different times, mice were sacrificed for autopsy, tumor nodules were counted and then removed for histology. Presence of metastases in visceral organs was also monitored. RESULTS: IST-Mes2 cells were unable to grow in nude mice. MM-B1 and IST-Mes3 cells were capable of growing in nude mice and formed tumor nodules in the pleura. Post-mortem examination showed that MPM cells progressively colonized the parietal and visceral pleura, the diaphragm, the mediastinum and, lastly the lung parenchyma. No pneumo-thorax was evidenced in the mice. Pleural effusions as well as lymph node metastases were observed only at later times. CONCLUSION: This model mimics the progression of human malignant mesothelioma and it is easy to perform and reproducible; therefore it can be useful to study human MPM biology and evaluate the efficacy of novel therapies.

Semaphorin-3A is expressed by tumor cells and alters T-cell signal transduction and function.

An important aspect of tumor progression is the ability of cancer cells to escape detection and clearance by the immune system. Recent studies suggest that several tumors express soluble factors interfering with the immune response. Here, we show that semaphorin-3A (Sema-3A), a secreted member of the semaphorin family involved in axonal guidance, organogenesis, and angiogenesis, is highly expressed in several tumor cells. Conditioned media of Sema-3A-transfected COS-7 cells or human recombinant Sema-3A inhibited primary human T-cell proliferation and cytokines production under anti-CD3 plus anti-CD28 stimulating conditions. Sema-3A also inhibited the activation of nonspecific cytotoxic activity in mixed lymphocyte culture (MLC), as measured against K-562 cells. In contrast, suppression of Sema-3A in tumor cells with a small interfering RNA (siRNA) augmented T-cell activation. The inhibitory effect of Sema-3A in T cells is mediated by blockade of Ras/mitogen-activated protein kinase (MAPK) signaling pathway. The presence of Sema-3A increased the activation of the Ras family small GTPase Rap1 and introduction of the dominant-negative mutant of Rap1 (Rap1N17) blunted the immunoinhibitory effects of Sema-3A. These results suggest that Sema-3A inhibits primary T-cell activation and imply that it can contribute to the T-cell dysfunction in the tumor microenvironment.

5-Lipoxygenase regulates senescence-like growth arrest by promoting ROS-dependent p53 activation.

5-Lipoxygenase (5LO) is involved in the production of leukotrienes and reactive oxygen species (ROS) from arachidonic acid. Its strong activation has been associated with several diseases like cancer and neurodegeneration. Here we show that 5LO activity increases during senescence-like growth arrest induced by oncogenic ras or culture history in both human and mouse embryo fibroblasts. Overexpression of 5LO promotes senescence-like growth arrest via a p53/p21-dependent pathway, and this occurs independently of telomerase activity. 5LO stabilizes p53 through phosphorylation at Ser15 and increases expression of the p53-transcriptional target p21. This is achieved by regulating ROS production. Indeed, ROS are increased in 5LO-arrested cells. Antioxidants and a low oxygen environment prevent 5LO-induced growth arrest. Finally, 5LO inhibition reduces the growth arrest induced by oncogenic ras or culture history and these effects are neutralized by the addition of exogenous ROS. These data link the 5LO pathway to oxidative crises of primary fibroblast and suggest that the ability of 5LO to induce senescence-like growth arrest may be important in the pathogenesis of 5LO-associated disorders.

5-lipoxygenase antagonizes genotoxic stress-induced apoptosis by altering p53 nuclear trafficking.

5-lipoxygenase (5-LO) promotes cancer cell proliferation and survival by unclear mechanisms. Here, we show that 5-LO expression and activity were induced by genotoxic agents in a p53-independent manner and antagonized p53- or genotoxic drug-induced apoptosis in a variety of cancer cells. 5-LO inhibited p53-governed transactivation of the pro-apoptotic genes bax and pig3 but not of p21(WAF1/CIP1) or mdm2. This may be explained by 5-LO capability to inhibit the binding of p53 to promyelocytic leukemia protein (PML) and p53 subnuclear relocalization into PML-nuclear bodies in response to genotoxic stress. Interestingly, 5-LO activity appears to be involved in nuclear retention and inactivation of wild-type p53 in malignant mesothelioma cells. In these cells, genetic or pharmacological inhibition of 5-LO enabled suppression of in vitro tumorigenicity by low doses of chemotherapeutic drugs. Together, these results uncover novel functions of 5-LO and contribute to the understanding of 5-LO involvement in tumor progression. Moreover, they provide a rationale to the therapeutic use of 5-LO inhibitors to enhance cancer chemosensitivity in selected tumors.

Induction of stem cell factor/c-Kit/slug signal transduction in multidrug-resistant malignant mesothelioma cells.

Malignant mesothelioma (MM) is strongly resistant to conventional chemotherapy by unclear mechanisms. We and others have previously reported that cytokine- and growth factor-mediated signal transduction is involved in the growth and progression of MM. Here, we identified a pathway that involves stem cell factor (SCF)/c-Kit/Slug in mediating multidrug resistance of MM cells. When we compared gene expression profiles between five MM cells and their multidrug-resistant (MM DX) sublines, we found that MM DX cells expressed both SCF and c-Kit and had higher mRNA levels of Slug. Knockdown of c-Kit or Slug expression with their respective small interfering RNA sensitized MM DX cells to the induction of apoptosis by different chemotherapeutic agents, including doxorubicin, paclitaxel, and vincristine. Transfection of c-Kit in parental MM cells in the presence of SCF up-regulated Slug and increased resistance to the chemotherapeutic agents. Moreover, MM cells expressing Slug showed a similar increased resistance to the chemotherapeutic agents. These results indicate that induction of Slug by autocrine production of SCF and c-Kit activation plays a key role in conferring a broad spectrum chemoresistance on MM cells and reveal a novel signal transduction pathway for pharmacological or genetic intervention of MM patients.

FLIP overexpression inhibits death receptor-induced apoptosis in malignant mesothelial cells.

Tumors have developed several forms of resistance to receptor-induced cell death. Here, we show that malignant mesothelial (MM) cell lines as well as primary MM cells and normal mesothelial (NM) cells express Fas and TNF-related apoptosis-inducing ligand (TRAIL) receptors DR4 and DR5. We found that, although Fas expression levels are comparable, only MM cells are resistant to cell death. Furthermore, MM cells show resistance to TRAIL-induced apoptosis. Caspase-8 (FLICE) is not activated by death receptors triggering in malignant cells whereas it is well activated by nonreceptor stimuli, such as UV radiation. We found that FLIP (FLICE-Inhibitory Protein) is constitutively expressed in all MM cell lines and is more expressed in primary MM cells than in NM cells. Knockdown of FLIP expression in MM cell lines, by a FLIPsiRNA, re-established the normal response to apoptosis induced by Fas or DR4/DR5, which was blocked by pretreatment with the caspase-8 inhibitor z-IETD-fmk. These results indicate that MM cells develop an intrinsic resistance to apoptosis induced by death receptors upregulating the expression of the antiapoptotic protein c-FLIP.

Experimental therapy of malignant mesothelioma: new perspectives from anti-angiogenic treatments.

We reviewed the published literature of clinical studies in malignant mesothelioma (MM), including phase II as well as older single-agent and combination chemotherapy trials with more than 15 patients. While response rates exceeding 30% have been achieved with established cytotoxic drugs in MM therapy, novel chemotherapeutic agents and their combinations appear more promising. This applies especially to the anti-metabolites (i.e. pemetrexed) that produced response rates of up to 45% in combination with platinum compounds. Moreover, agents targeting novel proliferative and survival pathways in MM are developed to improve treatment outcomes. Here, we focused on the role of several angiogenic growth factors in MM biology and the data of MM-oriented studies on angiostatic agents tested in a phase I-II trial. It seems likely that no single treatment modality will be effective by itself. Studies that use combinations of the newer agents, including angiostatic drugs, with chemotherapy, should be conducted.