Cancer metastasis reviews
-
Cancer metastasis reviews · Mar 2011
ReviewSomatostatin analogs for the treatment of neuroendocrine tumors.
Somatostatin is an important regulator of endocrine and exocrine secretion, affecting the release of many hormones. The effects of somatostatin are mediated through its interaction with one of five somatostatin receptors. Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) express multiple somatostatin receptors, making them excellent potential therapeutic targets. ⋯ More recently, somatostatin analogs have been shown to have antiproliferative effects, thus broadening the scope of their uses. In this review, we update the current data on the treatment of GEP-NETs with somatostatin analogs, with particular emphasis on the results of the PROMID study. In addition, we discuss the current state of knowledge of novel therapies against GEP-NETs, including the use of somatostatin analogs with broader receptor binding profiles, chimeric somatostatin-dopamine molecules, combinations of somatostatin analogs with other active chemotherapy agents, and peptide receptor-targeted radionuclide therapy.
-
Cancer initiation, progression, and invasion occur in a complex and dynamic microenvironment which depends on the hosts and sites where tumors develop. Tumors arising in mucosal tissues may progress in an inflammatory context linked to local viral and/or bacterial infections. At the opposite, tumors developing in immunoprivileged sites are protected from microorganisms and grow in an immunosuppressive environment. ⋯ In view of the prominent role of DC in the immune response, we suggest that the microenvironment of early-stage NSCLC may allow the in situ activation of the adaptive response. Finally, we find that the eyes or brain of mice with growing B cell lymphoma are infiltrated with T cells and that the cytokines produced ex vivo by the tumoral tissues have an impaired Th1 cytokine profile. Our work illustrates that the host and external tumor microenvironments are multifaceted and strongly influence tumor progression and anti-tumor immune responses.
-
Cancer metastasis reviews · Jun 2008
ReviewProtein phosphatase 2A (PP2A), a drugable tumor suppressor in Ph1(+) leukemias.
Protein phosphatase-2A (PP2A) is one of the major cellular serine-threonine phosphatases and is involved in the regulation of cell homeostasis through the negative regulation of signaling pathways initiated by protein kinases. As several cancers are characterized by the aberrant activity of oncogenic kinases, it was not surprising that a phosphatase like PP2A has progressively been considered as a potential tumor suppressor. Indeed, multiple solid tumors (e.g. melanomas, colorectal carcinomas, lung and breast cancers) present with genetic and/or functional inactivation of different PP2A subunits and, therefore, loss of PP2A phosphatase activity towards certain substrates. ⋯ Remarkably, drugs such as forskolin, 1,9-dideoxy-forskolin and FTY720 which lead to PP2A activation effectively antagonize leukemogenesis in both in vitro and in vivo models of these cancers. Thus, PP2A is now in the spotlight as a highly promising drugable target for the development of a new series of anticancer agents potentially capable of overcoming drug-resistance induced in patients by continuous exposure to kinase inhibitor monotherapy. Herein, we review current knowledge of PP2A biology and function with particular emphasis on its tumor suppressor activity and possible therapeutic implications in cancer.
-
Cancer metastasis reviews · Mar 2006
ReviewModifying the soil to affect the seed: role of stromal-derived matrix metalloproteinases in cancer progression.
In the 1980's, as the importance of matrix metalloproteinases (MMPs) in cancer progression was discovered, it was recognized that in most tumors these proteases were abundantly and sometimes exclusively expressed not by tumor cells, but by normal host-derived cells like fibroblasts, vascular endothelial cells, myofibroblasts, pericytes or inflammatory cells that contribute to the tumor microenvironment. Later experiments in mice deficient in specific MMPs revealed that host-derived MMPs play a critical role not only in tumor cell invasion, but also in carcinogenesis, angiogenesis, vasculogenesis and metastasis. Tumor cells secrete many factors, cytokines and chemokines that directly or indirectly increase the expression of these MMPs in the tumor microenvironment where they exert extracellular matrix (ECM) degrading and sheddase activities. The knowledge of the complex role that stromal-derived MMPs play in the interaction between tumor cells and stromal cells should allow us to consider specific windows in cancer treatment when MMP inhibition could have a valuable therapeutic effect.
-
Cancer metastasis reviews · Jan 2004
ReviewTreatment of colorectal cancer metastasis: the role of chemotherapy.
5-Fluorouracil (5-FU) has been the main chemotherapeutic agent for the treatment of colorectal cancer for four decades with modest efficacy. Modulation of 5-FU by leucovorin or continuous infusion improves the response rate, but overall survival duration remains approximately 12 months. Many oral fluoropyrimidines have been studied, including capecitabine, UFT, S-1, and Eniluracil. ⋯ Oxaliplatin plus 5-FU has offered another effective treatment option for colorectal cancer. Both 5-FU plus leucovorin in combination with CPT-11 or oxaliplatin are widely used first-line chemotherapies for advanced colorectal cancer. Optimal combinations and sequences of treatment are being studied, since several effective regimens have become available.