KRAS and NRAS mutation detection in circulating DNA from patients with metastatic colorectal cancer using BEAMing assay: Concordance with standard biopsy and clinical evaluation.

Patients with metastatic colorectal cancer (mCRC) are routinely screened for either K- and N-RAS to select the appropriate treatment. The present study aimed to evaluate the concordance between K- and NRAS status in the tissue (either primary tumor or metastasis) and the plasma of patients with mCRC and to identify the associations between K- and NRAS mutations in ctDNA and the clinicopathological parameters. Samples from a total of 31 patients with mCRC with measurable disease according to the Response Evaluation Criteria in Solid Tumors were analyzed. For all patients, K- and NRAS status was determined in the tissue by matrix-assisted laser desorption/ionization time of flight mass spectrometry. For the detection of RAS mutations in cell-free tumor DNA also defined as circulating tumor DNA (ctDNA), the OncoBEAM® RAS CRC kit (Sysmex Inostics) was used. A total of 6/31 tissue samples expressed wild-type KRAS, whereas 25/31 presented mutations. In addition, 7/31 plasma samples expressed wild-type KRAS, mutations were detected in 22/31 patients, and for 2/31 patients, the test did not provide a conclusive result. A total of 24/31 patients expressed wild-type NRAS, 6/31 had mutations and 1/21 was not informative. For the KRAS mutational status, a moderate concordance (agreement, 85.18%; Cohen's k, 0.513) between the tissue and plasma analysis was observed; for NRAS, a fair agreement (agreement, 83.33%; Cohen's k, 0.242) was obtained. In conclusion, both tissue and plasma analyses should be performed for the management of patients with mCRC. To better exploit the beads, emulsions, amplification, magnetics (BEAMing) technique in the clinical setting, studies aimed at determining the RAS status to monitor therapy and during follow-up are warranted.

Bridged bicyclic 2,3-dioxabicyclo[3.3.1]nonanes as antiplasmodial agents: Synthesis, structure-activity relationships and studies on their biomimetic reaction with Fe(II).

Despite recent advancements in its control, malaria is still a deadly parasitic disease killing millions of people each year. Progresses in combating the infection have been made by using the so-called artemisinin combination therapies (ACTs). Natural and synthetic peroxides are an important class of antimalarials. Here we describe a new series of peroxides synthesized through a new elaboration of the scaffold of bicyclic-fused/bridged synthetic endoperoxides previously developed by us. These peroxides are produced by a straightforward synthetic protocol and are characterized by submicromolar potency when tested against both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains. To investigate their mode of action, the biomimetic reaction of the representative compound 6w with Fe(II) was studied by EPR and the reaction products were characterized by NMR. Rationalization of the observed structure-activity relationship studies was performed by molecular docking. Taken together, our data robustly support the hypothesized mode of activation of peroxides 6a-cc and led to the definition of the key structural requirements responsible for the antiplasmodial potency. These data will pave the way in future to the rational design of novel optimized antimalarials suitable for in vivo investigation.