The inhibition of FGF receptor 1 activity mediates sorafenib antiproliferative effects in human malignant pleural mesothelioma tumor-initiating cells.

Background: Malignant pleural mesothelioma is an aggressive cancer, characterized by rapid progression and high mortality. Persistence of tumor-initiating cells (TICs, or cancer stem cells) after cytotoxic drug treatment is responsible for tumor relapse, and represents one of the main reasons for the poor prognosis of mesothelioma. In fact, identification of the molecules affecting TIC viability is still a significant challenge.

Molecular Pharmacology of Malignant Pleural Mesothelioma: Challenges and Perspectives From Preclinical and Clinical Studies.

Malignant pleural mesothelioma (MPM) is one of the deadliest and most heterogeneous tumors, highly refractory to multimodal therapeutic approach, including surgery, chemo- and radiotherapy. Preclinical and clinical studies exploring the efficacy of drugs targeting tyrosine kinases, angiogenesis and histone deacetylases, did not fulfil the expected clinical benefits. Thus, novel molecular targets should be identified from a definite knowledge of the unique biology and most relevant transduction pathways of MPM cells.

Sorafenib selectively depletes human glioblastoma tumor-initiating cells from primary cultures.

Glioblastomas are grade IV brain tumors characterized by high aggressiveness and invasiveness, giving patients a poor prognosis. We investigated the effects of the multi-kinase inhibitor sorafenib on six cultures isolated from human glioblastomas and maintained in tumor initiating cells-enriching conditions. These cell subpopulations are thought to be responsible for tumor recurrence and radio- and chemo-resistance, representing the perfect target for glioblastoma therapy.

Preclinical strategies targeted at non-small-cell lung cancer signalling pathways with striking translational fallout.

Over the past decades, a plethora of cytotoxic agents, administered alone or in combinations, have been prescribed for the treatment of non-small-cell lung cancer (NSCLC) but improvements regarding patient outcome remain disappointing. Therefore, additional therapeutic strategies are urgently required to increase response rate and survival. By the time researchers had begun to understand the processes involved in NSCLC development, the genetic aetiology of lung cancer had been progressively defined.

Preclinical studies identify novel targeted pharmacological strategies for treatment of human malignant pleural mesothelioma.

The incidence of human malignant pleural mesothelioma (hMPM) is still increasing worldwide. hMPM prognosis is poor even if the median survival time has been slightly improved after the introduction of the up-to-date chemotherapy. Nevertheless, large phase II/III trials support the combination of platinum derivatives and pemetrexed or raltitrexed, as preferred first-line schedule.

Receptor tyrosine kinase inhibitors and cytotoxic drugs affect pleural mesothelioma cell proliferation: insight into EGFR and ERK1/2 as antitumor targets.

Malignant pleural mesothelioma (MPM) is an aggressive chemotherapy-resistant cancer. Up-regulation of epidermal growth factor receptor (EGFR) plays an important role in MPM development and EGFR-tyrosine kinase inhibitors (TKIs) may represent novel therapeutic options. We tested the effects of the EGFR TKIs gefitinib and erlotinib and TKIs targeted to other growth factors (VEGFR and PDGFR), in comparison to standard antineoplastic agents, in two human MPM cell lines, IST-Mes2 and ZL55.

Combined chemotherapy with cytotoxic and targeted compounds for the management of human malignant pleural mesothelioma.

Human malignant pleural mesothelioma (hMPM) is an aggressive asbestos-associated cancer, the incidence of which is increasing and which, despite progress in diagnosis and therapy, continues to have a poor prognosis. Asbestos fibers induce aberrant cell signaling, leading to proto-oncogene activation and chemoresistance. In this review, we discuss the evolution of pharmacological management of hMPM up to the most recent advances.

Estrogen receptor β exerts tumor repressive functions in human malignant pleural mesothelioma via EGFR inactivation and affects response to gefitinib.

Background: The role of estrogen and estrogen receptors in oncogenesis has been investigated in various malignancies. Recently our group identified estrogen receptor beta (ERβ) expression as an independent prognostic factor in the progression of human Malignant Pleural Mesothelioma (MMe), but the underlying mechanism by which ERβ expression in tumors determines clinical outcome remains largely unknown. This study is aimed at investigating the molecular mechanisms of ERβ action in MMe cells and disclosing the potential translational implications of these results.

Gefitinib targets EGFR dimerization and ERK1/2 phosphorylation to inhibit pleural mesothelioma cell proliferation.

Altered EGFR activity is a causal factor for human tumor development, including malignant pleural mesotheliomas. The aim of the present study was the evaluation of the effects of Gefitinib on EGF-induced mesothelioma cell proliferation and the intracellular mechanisms involved. Cell proliferation, DNA synthesis and apoptosis were measured by MTT, thymidine incorporation and FACS analysis; EGFR, ERK1/2 and Akt expression and phosphorylation by Western blot, whereas receptor sites were analyzed by binding studies.

Different response of human glioma tumor-initiating cells to epidermal growth factor receptor kinase inhibitors.

Because a subpopulation of cancer stem cells (tumor-initiating cells, TICs) is believed to be responsible for the development, progression, and recurrence of many tumors, we evaluated the in vitro sensitivity of human glioma TICs to epidermal growth factor receptor (EGFR) kinase inhibitors (erlotinib and gefitinib) and possible molecular determinants for their effects. Cells isolated from seven glioblastomas (GBM 1-7) and grown using neural stem cell permissive conditions were characterized for in vivo tumorigenicity, expression of tumor stem cell markers (CD133, nestin), and multilineage differentiation properties, confirming that these cultures are enriched in TICs. TIC cultures were challenged with increasing concentrations of erlotinib and gefitinib, and their survival was evaluated after 1-4 days.

Imatinib mesylate enhances therapeutic effects of gemcitabine in human malignant mesothelioma xenografts.

Purpose: Platelet-derived growth factor receptor beta (PDGFRbeta), frequently activated in malignant mesothelioma, is a promising cancer therapeutic target. Imatinib mesylate (STI571; Glivec) is a selective inhibitor of tyrosine kinases as bcr-abl, c-kit, c-fms, and PDGFRbeta and enhances tumor drug uptake by reducing the interstitial fluid pressure. We previously showed that imatinib mesylate synergizes with gemcitabine and pemetrexed in PDGFRbeta-positive mesothelioma cells.

17beta-estradiol promotes breast cancer cell proliferation-inducing stromal cell-derived factor-1-mediated epidermal growth factor receptor transactivation: reversal by gefitinib pretreatment.

The coordinated activity of estrogens and epidermal growth factor receptor (EGFR) family agonists represents the main determinant of breast cancer cell proliferation. Stromal cell-derived factor-1 (SDF-1) enhances extracellular signal-regulated kinases 1 and 2 (ERK1/2) activity via the transactivation of EGFR and 17beta-estradiol (E2) induces SDF-1 production to exert autocrine proliferative effects. On this basis, we evaluated whether the inhibition of the tyrosine kinase (TK) activity of EGFR may control different mitogenic stimuli in breast tumors using the EGFR-TK inhibitor gefitinib to antagonize the proliferation induced by E2 in T47D human breast cancer cells.

Preliminary data suggestive of a novel translational approach to mesothelioma treatment: imatinib mesylate with gemcitabine or pemetrexed.

Background: Malignant mesothelioma is a cancer which is refractory to current treatments. Imatinib mesylate is a selective inhibitor of tyrosine kinases such as bcr-abl, c-Kit, c-Fms and platelet derived growth factor receptor beta (PDGFRbeta). PDGFRbeta is often overexpressed in mesothelioma cells and is a therapeutic target for imatinib in some solid tumours.

In vitro study of CI-994, a histone deacetylase inhibitor, in non-small cell lung cancer cell lines.

CI-994 (N-acetyldinaline) is a novel oral compound with a wide spectrum of antitumor activity in preclinical models, in vitro and in vivo. The mechanism of action may involve inhibition of histone deacetylation and cell cycle arrest. We studied the action of CI-994 on two non-small cell lung cancer (NSCLC) cell lines: A-549 (adenocarcinoma) and LX-1 (squamous cell carcinoma).

In vitro study of farnesyltransferase inhibitor SCH 66336, in combination with chemotherapy and radiation, in non-small cell lung cancer cell lines.

K-ras alterations have been reported in 20-30% of non-small cell lung cancer (NSCLC) and represent a suitable target for the development of novel anticancer agents, such as Farnesyl transferase inhibitors (FTi), a new class of agents inhibiting the post-translational modification of the K-ras proteins. The effectiveness of FTi SCH66336 in inhibiting cell proliferation and deranging cell cycle of NSCLC cell lines as well as its interaction with chemotherapy or radiation have been evaluated. The activity of FTi SCH66336, alone or in combination with paclitaxel, gemcitabine, and radiotherapy, was examined in 3 cell lines, A-549, LX-1 and CaLu-6, by colorimetric MTT assay.

Enhanced effectiveness of last generation antiblastic compounds vs. cisplatin on malignant pleural mesothelioma cell lines.

The purpose of this study was to examine the antiproliferative potentialities of a pool of new generation compounds (Paclitaxel, Docetaxel, Gemcitabine, Topotecan, SN-38) together with fenretinide, a synthetic derivative of retinoic acid, in comparison with the current first choice treatment cisplatin molecule, on a pool of human malignant pleural mesothelioma cell lines derived from either bioptic and pleural effusions samples. To evaluate the chemosensitivity features of malignant mesothelioma cells in vitro, we resorted to a rapid and reproducible colorimetric assay, a useful widely recognized tool for preclinical drug screening. In addition, by DNA content analysis and cellular morphologic assessment, we focused on the apoptosis as a potential mechanism of drug activity.

Interaction between novel anticancer agents and radiation in non-small cell lung cancer cell lines.

Integration of chemotherapy and radiation is the standard practice in the management of locally advanced inoperable NSCLC. To assess the biological interaction between third generation chemotherapeutic agents and radiation in non-small cell lung cancer (NSCLC) in vitro, we tested a number of different drugs (paclitaxel, docetaxel, gemcitabine, topotecan, SN-38 and cisplatin) combined with radiation, in lung cancer cell lines. Cellular chemosensitivity was determined, using the semi-automated colorimetric MTT assay, after 48, 72 and 96 h of exposure to increasing drug concentrations, (0.

The role of polypeptide growth factors in human carcinomas: new targets for a novel pharmacological approach.

The processes of cellular proliferation and progressive acquisition of a specialized phenotype show a high degree of coordination. In particular, these complex signaling networks mediating cell growth, differentiation, migration, and apoptosis are regulated in part by polypeptide growth factors that can act, by autocrine and/or paracrine mechanisms of action, as positive or negative modulators. Because these growth factors are unable to cross the hydrophobic cell membrane, they exert their effects via binding to cell surface receptors, most of which possess intrinsic tyrosine kinase activity.

Polysulfated heparinoids selectively inactivate heparin-binding angiogenesis factors.

Angiogenesis is a prerequisite for tumor expansion and metastasis. The angiogenic potential of the heparin-binding growth factors acidic fibroblast growth factor (FGF) and basic FGF has been demonstrated in various publications. We studied the inhibitory effects of suramin and the polysulfated heparinoids pentosan polysulfate, dextran sulfate, and fucoidan on the action of FGF.

Pre-clinical evaluation of new antineoplastic agents in NSCLC cell lines: evidence of histological subtype-dependent cytotoxicity.

The antiproliferative effect of paclitaxel, docetaxel, gemcitabine, topotecan, SN-38 and cis-platin was studied on 5 non-small cell lung cancer (NSCLC) cell lines, 3 of which were adenocarcinoma (ADK) and 2 squamous cell carcinoma (SCC). Cellular chemosensitivity was determined using the MTT in vitro assay after 48, 72 and 96 h of exposure to drug in concentration ranging from 0.001 to 100 microM.

New vs old fashioned oestradiol antagonists in mammary carcinoma: 'in vitro' and 'in vivo' pharmacological approaches.

The rationale underlying therapeutic strategies designed to inhibit the action of endogenous sex hormones in malignant breast cells is provided by the demonstration of their involvement in supporting the development and growth of breast carcinoma. The surgical removal of steroid-secreting glands, in order to reduce the level of oestrogens reaching their target tissues, has for years been substituted by the so-called endocrinotherapeutic approach, which is based on the counteraction of the steroid hormone activity by the hormonal receptor blockade with suitable antioestrogenic compounds. Over the past 25 years, the non-steroidal oestrogen antagonist tamoxifen has become the standard endocrine treatment for breast cancer.

Establishment of four new mesothelioma cell lines: characterization by ultrastructural and immunophenotypic analysis.

The aim of this study was to assess the biological characteristics of four new malignant mesothelioma (MM) cell lines. Since simian virus (SV)40 sequences have been recently detected in MM, SV40 large T antigen (Tag) expression was also analysed. MM cell lines were characterized by morphological, ultrastructural and cytogenetic analysis.

Responsiveness to hormone, growth factor and drug treatment of a human breast cancer cell line: comparison between early and late cultures.

Growth rate, morphology, and responsiveness to mitogenic stimuli and pharmacological treatments were evaluated in early and late cell passages derived from the same clone of the widely used MCF-7 human breast adenocarcinoma cell line. Our results indicate dissimilarities between early (E) and late (L) passages for some of the parameters analyzed. The cells that underwent many subcultivations grew faster than the others; both appeared homogeneous in size and shape.

Steroidal and nonsteroidal oestrogen antagonists in breast cancer: basic and clinical appraisal.

Endogenous sex hormones, such as oestrogens, control the development and growth of breast carcinoma. Blocking the binding between the steroid hormone and its receptor using anti-oestrogenic compounds is one of the possible ways of impeding the action of oestrogens at the level of their target tissues. The nonsteroidal, triphenylethylenic, anti-oestrogen tamoxifen has so far been the standard compound for endocrine treatment of breast cancer.

Establishment and preliminary characterization of human malignant mesothelioma cell lines.

Malignant mesothelioma is an aggressive and rare tumor of the mesothelium which arises in serosal cavities and is strongly related to asbestos exposure. The incidence of this tumor is still increasing because of the widespread use of asbestos over the past years and the long latency of this malignancy. The paucity of well-characterized in vitro human models and the consequent shortage of experimental pharmacological studies on mesothelioma reduce the success of its clinical management.