Angiogenesis is a key factor in the carcinogenesis process. In oncological practice, angiogenesis inhibition, mainly through the blockade of the VEGF family and its receptors, has been robustly ...demonstrated to produce clinical benefits and, in specific disease subsets such as colorectal cancer, to extend the overall survival of treated patients. VEGF is a multifunctional growth factor that mediates its functions through cognate receptors on endothelial cells and it has been discovered for its capability to induce macromolecule hyperpermeability in veins and venules. Several approaches have been taken to target angiogenesis in cancer: drugs that target one or more soluble ligands of the VEGF family, drugs that selectively inhibit one or more receptors of the VEGF receptor family, and drugs that inhibit VEGF receptor(s) among other, non VEGF-related targets. At present, two compounds have shown significant clinical activity, bevacizumab, Avastin® and aflibercept, Zaltrap®, and only one of these (bevacizumab) has so far been registered for use in clinical practice. In the present review, we explore and summarize the main features of the angiogenetic process, concerning in particular a common and potentially lethal disease as colorectal cancer. We overview the molecular pathways that characterize angiogenesis, focusing on VEGF family, the current applications and limitations of its blockade in oncology, and the hypothetical future perspectives of anti-angiogenic therapy.
Molecular characterization of an Italian series of sporadic GISTs Origone, P.; Gargiulo, S.; Mastracci, L. ...
Gastric cancer : official journal of the International Gastric Cancer Association and the Japanese Gastric Cancer Association,
10/2013, Letnik:
16, Številka:
4
Journal Article
Recenzirano
Purpose
Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors of the gastrointestinal tract. Most (80 %) contain activating mutations in the KIT receptor tyrosine kinase, roughly 10 % in ...platelet-derived growth factor receptor-alpha (PDGFRA). In a small subset, BRAF mutations are an alternative molecular pathway. GISTs respond well to imatinib, but low response is seen in patients with wild-type KIT or PDGFRA. Resistance has also been reported as a result of mutations in downstream effectors such as BRAF.
Methods
We provide here a molecular characterization of a series of primary GISTs from Italian patients. Of 121 GIST cases diagnosed between 2000 and 2012, 83 were evaluated by PCR amplification and direct sequencing for mutations in KIT exons 8, 9, 11, 13, and 17, PDGFRA exons 12, 14, and 18, and BRAF exon 15. Eighty-one GISTs also underwent K-RAS testing.
Results
Sixty-four GISTs were positive: 55 had mutations in KIT and 9 in PDGFRA; 16 patients were mutation negative. Three samples came from NF1 patients and were KIT- and PDGFRA negative. Overall, we identified six novel mutations in KIT (p.K550_M552delinsL, p.Q556_W557delinsG p.Q556_G575del, p.W557_V559delinsQ p.P573_R588dup, p.G592_K593dup) and one novel mutation in PDGFRA (p.D842_N848delinsVDV), thus contributing to widening the spectrum of known mutations in GIST tumors and confirming the most frequently altered regions underlying GIST development.
Conclusions
Among the 64 KIT- and PDGFRA-positive sporadic patients in our series, no BRAF or KRAS mutations were identified, suggesting that co-occurrence of these mutations is likely to be rare in the northwestern Italian population and not a frequent cause of primary resistance to imatinib in KIT-positive GIST patients.
Over the past two decades, progresses in colorectal cancer treatment have significantly improved patient survival and quality of life. However, unresectable metastatic colorectal cancer remains ...virtually incurable, making the search for new effective therapeutics mandatory. An important limitation to the development of new agents has been the difficulty to exploit mutated tumor suppressors or "undruggable" oncogenes as a target. Recently, evidence that mutations in tumor suppressors, such as BRCA1/2, make cancer cells highly susceptible to inhibitors of a compensatory DNA repair pathway poly-(ADP-ribose) polymerase 1 (PARP1) has broadened the range of possible therapeutic targets by extending it to gene products that are in a "synthetic lethal" relationship with oncogenes and tumor suppressors. Inhibition of such targets blocks specific buffer-mechanisms that are required for survival in the presence of defined oncogenic mutations, but not in their absence. As a consequence, selective elimination of mutation-bearing cells results. This approach has led to identify compounds that are highly active in the presence of different types of mutated tumor suppressors and oncogenes, including DNA repair genes, RAS, and Myc. In addition, ongoing studies promise to identify new mechanisms which, when pharmacologically interfered with, will selectively eradicate mutated cancer cells. Here, we revise and discuss these new aspects of cancer biology and highlight their potential applications in colorectal cancer treatment.
This review article is part of a special Current Cancer Drug Targets issue devoted to colorectal cancer and molecularly targeted treatments. In our paper we made an attempt to connect more basic ...aspects with preclinical, pharmacological / therapeutic and clinical aspects. Reconstruction of a Molecular Interaction Map (MIM) comprising an important part of the G0 - G1 - S cell cycle transition, was a major component of our review. Such a MIM serves also as a convenient / organized database of a large set of important molecular events. The frequency of mutated / altered signaling-proteins indicates the importance of this signaling-network region. We have considered problems at different scale levels. Our MIM works at a biochemical-interaction level. We have also touched the multi-cellular dynamics of normal and aberrant colon crypts. Until recently, dynamic simulations at a biochemical or multi-cellular scale level were considered as a sort of esoteric approach. We tried to convince the reader, also on the basis of a rapidly growing literature, mostly published in high quality journals, that suspicion towards simulations should dissipate, as the limitations and advantages of their application are better appreciated, opening the door to their permanent adoption in everyday research. What is really required is a more interdisciplinary mentality and an interdisciplinary approach. The prize is a level of understanding going beyond mere intuition.
The median survival of women with metastatic breast cancer (MBC) is 18-24 months, and fewer than 5% are alive and disease free at 5 years. We report toxicity and survival in a cohort of MBC patients ...receiving high-dose chemotherapy (HDC) with autologous hematopoietic SCT (AHSCT) in Italy between 1990 and 2005. Data set for survival analysis has been obtained for 415 patients. Clinical parameters including probability of transplant-related mortality (TRM), PFS and OS. With a median follow-up of 27 months (range 0-172), OS and PFS at 5 and 10 years in the whole population were 47/23 and 32/14%, respectively. A total 239 patients are alive with a median follow-up of 33 months (range 2-174). Survival was significantly more pronounced in patients harboring hormone receptor positive tumors (P=0.028), without visceral metastases (P=0.009) and in women with chemosensitive disease (P<0.0001). Sixty eight patients (20.4%) who received HDC in partial response, stable or progressive disease underwent conversion to CR. TRM was 2.5% overall and 1.3% since 2000. Our findings suggest that could be a role for HDC and AHSCT in delaying disease progression and possibly cure a subset of MBC patient harboring chemosensitive tumors.
Lapatinib, a dual HER2 and EGFR tyrosine kinase inhibitor is highly active in HER2+ breast cancer. However, its efficacy is limited by either primary or acquired resistance. Although mutations in ras ...genes are rarely found in breast cancer, H-ras overexpression is frequently observed. Moreover, genetic alterations that do not directly involve ras such as Brk amplification, ultimately result in increased ras signaling. Using SKBR3 cells, a HER2+ breast cancer cell line that is naturally devoid of mutations in PI3KCA, PTEN, BRAF, and ras we show that both H-ras overexpression and expression of an oncogenic ras allele (ras V12) reduce susceptibility to lapatinib in analogy to what observed with activating PI3KCA mutations and with a constitutively active form of Akt. Importantly, we found that resistance to lapatinib due to ras overexpression or to ras V12 is overcome by MEK inhibition with U0126, suggesting a key role for the MEK-Erk pathway in ras-induced resistance. Similar results were obtained in BT474 cells, another HER+ breast cancer cell line. Therefore, our data indicate that overexpressed/mutated ras may act as a biological modifier of the response to lapatinib. Combining MEK inhibitors with lapatinib may help overcome this form of resistance and increase the efficacy of lapatinib in these tumors.
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