Dietary Polyphenols Effects on Focal Adhesion Plaques and Metalloproteinases in Cancer Invasiveness.

Focal adhesion plaques (FAPs) play an important role in the communication between cells and the extracellular matrix (ECM) and in cells' migration. FAPs are macromolecular complexes made by different proteins which also interact with matrix metalloproteinases (MMPs). Because of these fundamental properties, FAPs and MMPs are also involved in cancer cells' invasion and in the metastatic cascade. The most important proteins involved in FAP formation and activity are (i) integrins, (ii) a complex of intracellular proteins and (iii) cytoskeleton proteins. The latter, together with MMPs, are involved in the formation of filopodia and invadopodia needed for cell movement and ECM degradation. Due to their key role in cancer cell migration and invasion, MMPs and components of FAPs are often upregulated in cancer and are thus potential targets for cancer therapy. Polyphenols, a large group of organic compounds found in plant-based food and beverages, are reported to have many beneficial healthy effects, including anticancer and anti-inflammatory effects. In this review, we discuss the growing evidence which demonstrates that polyphenols can interact with the different components of FAPs and MMPs, inhibit various pathways like PI3K/Akt, lower focal adhesion kinase (FAK) phosphorylation and decrease cancer cells' invasiveness, leading to an overall antitumoral effect. Finally, here we highlight that polyphenols could hold potential as adjunctive therapies to conventional cancer treatments due to their ability to target key mechanisms involved in cancer progression.

Antitumoral effects of Bortezomib in malignant mesothelioma: evidence of mild endoplasmic reticulum stress in vitro and activation of T cell response in vivo.

BACKGROUND: Malignant mesothelioma (MM) is a rare tumor with a dismal prognosis. The low efficacy of current treatment options highlights the urge to identify more effective therapies aimed at improving MM patients' survival. Bortezomib (Bor) is a specific and reversible inhibitor of the chymotrypsin-like activity of the 20S core of the proteasome, currently approved for the treatment of multiple myeloma and mantle cell lymphoma. On the other hand, Bor appears to have limited clinical effects on solid tumors, because of its low penetration and accumulation into tumor tissues following intravenous administration. These limitations could be overcome in MM through intracavitary delivery, with the advantage of increasing local drug concentration and decreasing systemic toxicity. METHODS: In this study, we investigated the effects of Bor on cell survival, cell cycle distribution and modulation of apoptotic and pro-survival pathways in human MM cell lines of different histotypes cultured in vitro. Further, using a mouse MM cell line that reproducibly forms ascites when intraperitoneally injected in syngeneic C57BL/6 mice, we investigated the effects of intraperitoneal Bor administration in vivo on both tumor growth and the modulation of the tumor immune microenvironment. RESULTS: We demonstrate that Bor inhibited MM cell growth and induced apoptosis. Further, Bor activated the Unfolded Protein Response, which however appeared to participate in lowering cells' sensitivity to the drug's cytotoxic effects. Bor also affected the expression of EGFR and ErbB2 and the activation of downstream pro-survival signaling effectors, including ERK1/2 and AKT. In vivo, Bor was able to suppress MM growth and extend mice survival. The Bor-mediated delay of tumor progression was sustained by increased activation of T lymphocytes recruited to the tumor microenvironment. CONCLUSIONS: The results presented herein support the use of Bor in MM and advocate future studies aimed at defining the therapeutic potential of Bor and Bor-based combination regimens for this treatment-resistant, aggressive tumor.

Combined treatment with inhibitors of ErbB Receptors and Hh signaling pathways is more effective than single treatment in reducing the growth of malignant mesothelioma both in vitro and in vivo.

Malignant mesothelioma (MM) is a rare orphan aggressive neoplasia with low survival rates. Among the other signaling pathways, ErbB receptors and Hh signaling are deregulated in MM. Thus, molecules involved in these signaling pathways could be used for targeted therapy approaches. The aim of this study was to evaluate the effects of inhibitors of Hh- (GANT-61) and ErbB receptors (Afatinib)-mediated signaling pathways, when used alone or in combination, on growth, cell cycle, cell death and autophagy, modulation of molecules involved in transduction pathways, in three human MM cell lines of different histotypes. The efficacy of the combined treatment was also evaluated in a murine epithelioid MM cell line both in vitro and in vivo. This study demonstrated that combined treatment with two inhibitors counteracting the activation of two different signaling pathways involved in neoplastic transformation and progression, such as those activated by ErbB and Hh signaling, is more effective than the single treatments in reducing MM growth in vitro and in vivo. This study may have clinical implications for the development of targeted therapy approaches for MM.