[Show abstract][Hide abstract] ABSTRACT: Recent preclinical evidence has suggested that Ewing Sarcoma (ES) bearing EWSR1-ETS fusions could be particularly sensitive to PARP inhibitors (PARPinh) in combination with DNA damage repair (DDR) agents. Trabectedin is an antitumoral agent that modulates EWSR1-FLI1 transcriptional functions, causing DNA damage. Interestingly, PARP1 is also a transcriptional regulator of EWSR1-FLI1, and PARPinh disrupts the DDR machinery. Thus, given the impact and apparent specificity of both agents with regard to the DNA damage/DDR system and EWSR1-FLI1 activity in ES, we decided to explore the activity of combining PARPinh and Trabectedin in in vitro and in vivo experiments. The combination of Olaparib and Trabectedin was found to be highly synergistic, inhibiting cell proliferation, inducing apoptosis, and the accumulation of G2/M. The drug combination also enhanced γH2AX intranuclear accumulation as a result of DNA damage induction, DNA fragmentation and global DDR deregulation, while EWSR1-FLI1 target expression remained unaffected. The effect of the drug combination was corroborated in a mouse xenograft model of ES and, more importantly, in two ES patient-derived xenograft (PDX) models in which the tumors showed complete regression. In conclusion, the combination of the two agents leads to a biologically significant deregulation of the DDR machinery that elicits relevant antitumor activity in preclinical models and might represent a promising therapeutic tool that should be further explored for translation to the clinical setting.
[Show abstract][Hide abstract] ABSTRACT: In any disease, the knowledge of the natural history of untreated cases provides a real background against which the real advantages of a new treatment itself are judged. Fortunately, in the present days, there are scant data on outcomes in patients with untreated breast cancer. In an attempt to provide this background against which the virtues of current curative and palliative treatments can be more accurately assessed, we have reviewed the literature regarding published untreated breast cancer series. Taking into consideration all the difficulties of analyzing reports written on the last half of the nineteenth century or on the first half of the twentieth century, in most reports, patients survived almost 3–4 years without any type of treatment. Worth mentioning, approximately 5–10 % of untreated patients lived longer than 10 years. Thus, the spectrum of clinical aggressiveness of untreated breast cancer varies between virulence and chronic disease.
These facts should be taken into account when considering the value of current treatments for early-stage disease.
Medical Oncology 02/2015; 32(2):466. DOI:10.1007/s12032-014-0466-x · 2.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Trabectedin is the first marine-derived anti-neoplastic drug approved for the treatment of advanced soft tissue sarcoma and, in combination with pegylated liposomal doxorubicin, for the treatment of patients with relapsed platinum-sensitive ovarian cancer. From the beginning of its development, trabectedin showed some peculiar properties that clearly distinguished it from other anti-cancer drugs. In this mini-review, we will outline the current state of knowledge regarding the mode of action of trabectedin, which appears to represent a new class of anti-neoplastic drugs acting both on cancer cells and on the tumour microenvironment.British Journal of Cancer advance online publication 22 April 2014; doi:10.1038/bjc.2014.149 www.bjcancer.com.
British Journal of Cancer 04/2014; 111(4). DOI:10.1038/bjc.2014.149 · 4.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The prevailing paradigm states that cancer cells acquire multiple genetic mutations in oncogenes or tumor suppressor genes whose respective activation/up-regulation or loss of function serve to impart aberrant properties, such as hyperproliferation or inhibition of cell death. However, a tumor is now considered as an organ-like structure, a complex system composed of multiple cell types (e.g., tumor cells, inflammatory cells, endothelial cells, fibroblasts, etc.) all embedded in an inflammatory stroma. All these components influence each other in a complex and dynamic cross-talk, leading to tumor cell survival and progression. As the microenvironment has such a crucial role in tumor pathophysiology, it represents an attractive target for cancer therapy. In this review, we describe the mechanism of action of trabectedin and plitidepsin as an example of how these specific drugs of marine origin elicit their antitumor activity not only by targeting tumor cells but also the tumor microenvironment.
[Show abstract][Hide abstract] ABSTRACT: PM060184 belongs to a new family of tubulin-binding agents originally isolated from the marine sponge Lithoplocamia lithistoides. This compound is currently produced by total synthesis and is under evaluation in clinical studies in patients with advanced cancer diseases. It was recently published that PM060184 presents the highest known affinities among tubulin-binding agents, and that it targets tubulin dimers at a new binding site. Here, we show that PM060184 has a potent antitumor activity in a panel of different tumor xenograft models. Moreover, PM060184 is able to overcome P-gp mediated resistance in vivo, an effect that could be related to its high binding affinity for tubulin. To gain insight into the mechanism responsible of the observed antitumor activity, we have characterized its molecular and cellular effects. We have observed that PM060184 is an inhibitor of tubulin polymerization that reduces microtubule dynamicity in cells by 59%. Interestingly, PM060184 suppresses microtubule shortening and growing at a similar extent. This action affects cells in interphase and mitosis. In the first case, the compound induces a disorganisation and fragmentation of the microtubule network and the inhibition of cell migration. In the second case, it induces the appearance of multipolar mitosis and lagging chromosomes at the metaphase plate. These effects correlate with prometaphase arrest and induction of caspase-dependent apoptosis or appearance of cells in a multinucleated interphase-like state unrelated to classical apoptosis pathways. Taken together, these results indicate that PM060184 represents a new tubulin binding agent with promising potential as an anticancer agent.