Dosimetrically motivated beam-angle optimization for non-coplanar arc radiotherapy with and without dynamic collimator rotation.

BACKGROUND: Non-coplanar techniques have shown to improve the achievable dose distribution compared to standard coplanar techniques for multiple treatment sites but finding optimal beam directions is challenging. Dynamic collimator trajectory radiotherapy (colli-DTRT) is a new intensity modulated radiotherapy technique that uses non-coplanar partial arcs and dynamic collimator rotation. PURPOSE: To solve the beam angle optimization (BAO) problem for colli-DTRT and non-coplanar VMAT (NC-VMAT) by determining the table-angle and the gantry-angle ranges of the partial arcs through iterative 4π fluence map optimization (FMO) and beam direction elimination. METHODS: BAO considers all available beam directions sampled on a gantry-table map with the collimator angle aligned to the superior-inferior axis (colli-DTRT) or static (NC-VMAT). First, FMO is performed, and beam directions are scored based on their contributions to the objective function. The map is thresholded to remove the least contributing beam directions, and arc candidates are formed by adjacent beam directions with the same table angle. Next, FMO and arc candidate trimming, based on objective function penalty score, is performed iteratively until a desired total gantry angle range is reached. Direct aperture optimization on the final set of colli-DTRT or NC-VMAT arcs generates deliverable plans. colli-DTRT and NC-VMAT plans were created for seven clinically-motivated cases with targets in the head and neck (two cases), brain, esophagus, lung, breast, and prostate. colli-DTRT and NC-VMAT were compared to coplanar VMAT plans as well as to class-solution non-coplanar VMAT plans for the brain and head and neck cases. Dosimetric validation was performed for one colli-DTRT (head and neck) and one NC-VMAT (breast) plan using film measurements. RESULTS: Target coverage and conformity was similar for all techniques. colli-DTRT and NC-VMAT plans had improved dosimetric performance compared to coplanar VMAT for all treatment sites except prostate where all techniques were equivalent. For the head and neck and brain cases, mean dose reduction-in percentage of the prescription dose-to parallel organs was on average 0.7% (colli-DTRT), 0.8% (NC-VMAT) and 0.4% (class-solution) compared to VMAT. The reduction in D2% for the serial organs was on average 1.7% (colli-DTRT), 2.0% (NC-VMAT) and 0.9% (class-solution). For the esophagus, lung, and breast cases, mean dose reduction to parallel organs was on average 0.2% (colli-DTRT) and 0.3% (NC-VMAT) compared to VMAT. The reduction in D2% for the serial organs was on average 1.3% (colli-DTRT) and 0.9% (NC-VMAT). Estimated delivery times for colli-DTRT and NC-VMAT were below 4 min for a full gantry angle range of 720°, including transitions between arcs, except for the brain case where multiple arcs covered the whole table angle range. These times are in the same order as the class-solution for the head and neck and brain cases. Total optimization times were 25%-107% longer for colli-DTRT, including BAO, compared to VMAT. CONCLUSIONS: We successfully developed dosimetrically motivated BAO for colli-DTRT and NC-VMAT treatment planning. colli-DTRT and NC-VMAT are applicable to multiple treatment sites, including body sites, with beneficial or equivalent dosimetric performances compared to coplanar VMAT and reasonable delivery times.

Discovery of a first-in-class Aurora A covalent inhibitor for the treatment of triple negative breast cancer.

Aurora kinases, which belong to the serine/threonine protein family, play critical roles in the regulation of the cell cycle and mitotic spindle assembly. They are frequently highly expressed in various types of tumors, and the use of selective Aurora kinase inhibitors has become a potential treatment option for cancer therapy. Despite the development of some reversible Aurora kinase inhibitors, none has been approved for clinical use yet. In this study, we report the discovery of the first-in-class irreversible Aurora A covalent inhibitors that target a cysteine residue at the substrate binding site. These inhibitors were characterized in enzymatic and cellular assays, and 11c exhibited selective inhibition to normal and cancer cells, as well as to Aurora A and B kinases. The covalent binding of 11c to Aurora A was confirmed by SPR, MS, and enzyme kinetic analysis, and Cys290-mediated covalent inhibition was supported through a bottom-up analysis of inhibitor-modified targets. Moreover, Western blotting assays were conducted on cells and tissues, and cellular thermal shift assays (CETSA) were further performed on cells to demonstrate the selectivity to Aurora A kinase. 11c displayed comparable therapeutic efficacy in an MDA-MB-231 xenograft mouse model relative to the positive control ENMD-2076, while requiring only half the dose of ENMD-2076. These results confirmed that 11c may be a promising drug candidate for the treatment of triple negative breast cancer (TNBC). Our work may provide a new perspective on the design of covalent inhibitors of Aurora kinase.

[1,1'-Bis(diphenyl-phosphan-yl)ferrocene-κP,P']dichloridocadmium(II) dichloro-methane disolvate.

In the title complex, [CdFe(C(17)H(14)P)(2)Cl(2)]·2CH(2)Cl(2), the Cd(II) atom has a distorted tetra-hedral coordination geometry by two chloride anions and two P atoms of 1,1'-bis-(diphenyl-phosphan-yl)ferrocene. In the crystal, complex mol-ecules are linked into a three-dimensional network by C-H⋯Cl hydrogen bonds involving the dichloro-methane solvent mol-ecules.

(Ferrocene-carboxyl-ato-κO)triphenyl-tin(IV).

In the title compound, [FeSn(C(5)H(5))(C(6)H(5))(3)(C(6)H(4)O(2))], the Sn(IV) atom displays a distorted tetra-hedral coordination geometry, provided by one O atom of the monodentate ferrocene-carboxyl-ate ligand [Sn-O = 2.079 (2) Å] and by three C atoms of the three phenyl groups [average Sn-C = 2.130 (4) Å]. No classic hydrogen bonds or inter-molecular inter-actions are observed in the crystal.

Di-µ-thio-cyanato-bis-{[1,2-bis-(diiso-propyl-phosphan-yl)-1,2-dicarba-closo-dodeca-borane]silver(I)}.

The title compound, [Ag(2)(NCS)(2)(C(14)H(38)B(10)P(2))(2)], was synthesized by the reaction of 1,2-bis-(diiso-propyl-phos-phan-yl)-1,2-dicarba-closo-dodeca-borane with AgSCN. The diisopropyl-phosphanyl-closo-carborane ligand is coordinated in a bidentate manner to the Ag(I) atom through the two P atoms. The coordination of the Ag(I) atom is distorted tetra-hedral, in which two vertices are formed by the P atoms of the chelating diphosphine ligand, and the other two are occupied by the S and N atoms of the two bridging thio-cyanate anions, leading to a centrosymmetric binuclear complex. The distance between the two C atoms in the carborane skeleton is 1.851 (6) Å.